Call Center Glossary

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Call center terminologies are sometimes difficult to remember even for experienced and highly qualified managers. Another issue is that a great part of contact center terminology is transformed and generally used as call center abbreviations. How no to confuse in such conditions?  As we understand how difficult it is to find some call center terminology on the Internet, and how much time it can consume, we have created this all-in-one glossary where all needed call center terminologies and call center abbreviations are included. Just use the Ctr+F, or navigate through the sections to find what you need. This dictionary includes also short, but complete descriptions of all the contact center terminology.  Bookmark this link to have unlimited access to the entire call center terminology wherever you are. 

In this article you will find:

A section

B section

C section

D section

E section

F section

H section

I section

K section

L section

M section

N section

O section

P section

Q section

R section

S section

T section

U section

V section

W section


A section

Abandoned Call

This term refers both to inbound and outbound calls. It is an inbound call abandoned by the caller before it has reached the agent. Or an outbound call that was terminated by a dialer when it was answered by a callee.

Abandon Call Rate

The percentage of outbound calls, where the connection was established with the live individual but terminated by a caller before the connection with the agent.

ACD - Automatic Call Distributor

A telephone system that routes calls to the most appropriate agent based on different parameters (like business hours, IVR selection, the longest available agent, etc.) and puts callee in the queue if no agent is available.

ACW - After-Call Work

A period of time immediately after the conversation with the customer is completed when the agent does all the work that is related to the customer (entering data, filling out forms, making necessary outbound calls).

Agent Occupancy (Utilisation Rate)

Agent occupancy is a period of time that an agent spends on call-related activity. Utilization Rate means a total logged-in time at work that may include other activities such as training sessions, meetings, and so on.

Agent Status

The agent's status at a particular moment. For example Ready, Reserved, Talking, Working, Not Ready.

Answered Call

A call that reached an agent or team and was answered.

Auto Attendant

A system that directs calls based on what the caller selected from the interactive menu. Auto Attendant offers the caller options to respond (for example, "press one for this", "press two for that", etc.) and then routes to ACD and to a specific destination.

Automatic Number Identification

The telephony tool that uncovers the caller’s phone number and shows it on the display. 

Automatic Speech Recognition

The tool that allows the IVR system to recognize caller’s phrases and requests and help them pass through menus or find needed information faster. 

Application Program Interface (API)

The interface that allows transferring data between different applications to speed up the data receiving and eliminate the duty to switch between various tools. In the contact center industry, it is mostly used to gather information from different systems in one interface of the call center software, and to return the event with updated data after each call. 

Application Service Provider

The firm that develops, maintains, and updates the software solution, and finally provides it to its customers via the Internet. 

Average Hold Time

Duration of time spent when the caller has been on hold. Agents use this mode to find some additional info about the customer’s request or to escalate or transfer the call. 

Average Handling Time (AHT)

The average amount of time spent by an agent to handle calls. It includes both talk time, hold time, and after-call work.

Average Speed of Answer (or Average Wait Time, or Average Time in Queue)

The average amount of time an agent needs to answer a typical call. Is counted from the moment of the first ring to the moment of taking the phone by the operator. 

Average Talk Time

The average time an agent spends talking to customers.

Average Time to Abandonment

The average amount of time that a customer waits in the queue before hanging up.

B section

Business Continuity Plan

The plan that contains all potential breakdown or emergency scenarios, and the rules of how to act in such situations. The main purpose of the plan is to create clear guidelines for establishing the call center’s stability and ability to work even in case of emergency. 

Blended agents

Agents that are trained to deal with both inbound and outbound calls.

Blocked Call

The incoming call cannot be connected immediately. It can happen because of two reasons: 1) there are no available circuits at the moment and 2) ACD is programmed not to put calls in the queue when the defined threshold is reached.

Business Process Outsourcing (BPO)

Contracting of business tasks to a third party. This term typically means moving call centers and other business functions to lower-cost countries.

C section


An option for a customer to order the call from agents when they will become available. This feature is mostly used to avoid making customers stay in queues. 

Call Avoidance

A strategy to handle low-value or unwanted calls. For example, a call center may decide to eliminate repeated calls to avoid failure or implement call automation through self-service.

Call Barging

This call monitoring mode is used when an agent can’t handle the issue on their own and the manager joins the dialog to help them.

Call Blending

Mixing incoming and outgoing calls for specific agent teams. For example, when inbound call volume is low, the system can route calls from outbound campaigns to the inbound agents. Or, when there is peak demand for inbound calls outbound agents can be involved.

Call Center (Call Centre)

A department or an office that specializes in handling telephone and voice calls by a team of advisors or agents who deal with new and existing customers. Call centers (call centres) are inbound, outbound, or blended (handling both types of calls).

Call Center Manager

A person who is responsible for the budget, operation, and business performance of the call center.

Call center management

The set of actions, tactics, and methods of managing processes in a call center to improve efficiency, productivity, and other indicators. 

Call Center Software

Software that helps businesses to manage incoming and outgoing voice interactions with customers and prospects. 


A detailed report of all calls that have been received or performed(inbound and outbound calls) by the team during the selected period of time. Contains many metrics, such as call volume, abandonment rate, average handling time, average response time, average wait time, and so on. 

Caller ID

A feature in telephone systems, including VoIP, that allows a calling party to identify a caller's telephone number.

Call Monitoring Modes

The modes in which a call center manager can join the live conversation to help an agent or to monitor them. There are three call monitoring modes: call barging, hidden mode, and call whispering. Learn more about call center quality monitoring

Call Recording

A feature that can record and store calls. It helps to implement an effective call handling quality process.

Call Routing

The process of transferring incoming calls to certain agents that is based on predefined criteria.


A telecommunications service provider (TSP) that connects the public with public switched telephone networks (PSTN) or mobile networks.


Self-service systems that deliver automated answers to customer messages. Also known as virtual assistants.

Churn Rate

The percentage of customers who stopped a business relationship with a company during a given period.

Cloud Contact Center (also CCaaS, Call Center as Service)

A contact center that operates in a cloud-based infrastructure. This is an evolution of an on-site contact center.

Customer Experience Management

The method of management that is based on tracking customer interactions and behavior to meet their expectations, fulfill wishes, and achieve a higher level of customer satisfaction and loyalty. 

Customer Satisfaction

The rate that shows how positive the customer's impression is of products and services, or interaction with the company. 

Customer Sentiment

The rate that shows positive feelings towards products and services provided by the company. The more interactions customers have with the company after purchasing from it - the higher this score is. 

Customer Journey

The whole experience of the customer after all his interactions with the company. The visualization of all his interactions is called a customer journey map.

Customer Experience

The rate that shows how the customer evaluates his experience with the company after finishing his customer journey. 

Customer Loyalty

The rate that shows how strong the customer's sentiment is toward the company. This score directly influences the customer retention rate and the chance of additional purchases. 

Customer Retention

The rate that shows how likely the customer is to stay with the company during the selected period of time. 

Cold Call

An unsolicited outgoing call that is made by an agent to a prospective customer, usually with the intention to sell or introduce some product or service. Learn more about cold calling


An ability to act according to an order or a set of rules either internal or external to a company. 

Computer Telephony Integration (CTI)

A method of combining your telephone system with your database. As a rule, this enables you to show the caller's details on the agent's screen when the call connects (Screen Pop). CTI can be used in various cases, for instance, in call routing. This method has huge advantages for business, but it can be deployed only in a limited way because of quite complex integration.

Contact Center (Contact Centre)

A department or an office that handles customer inquiries from all available channels (voice calls, e-mails, social media, instant messaging). Learn about the difference between a call center and contact center

Contact Center as a Service (CCaaS)

A model of software deployment where a company buys technology that is operated by a vendor. As a rule, CCaaS is deployed in the cloud but sometimes maybe on-premise. This is a cost-effective option that enables companies to reduce IT, integration, and support costs.

Contact Center Quality Assurance

Quality assurance is a process that ensures products and services meet the company's standards. In the contact center, this process usually means monitoring the agents’ interactions with customers.

Cost Per Call

Cost per call is a business metric that allows call centers to calculate the total cost involved in handling calls during a specific period of time (an hour, a week, a month, a year, etc.). The cost per call could include things such as wages for call center staff, per-minute costs or toll-free number costs on the telephone bill, utilities for the call center itself, and the cost of the equipment and software used in order to adjust inbound and outbound calls.

CRM system (Customer relationship management systems)

A system that is designed to manage all the company's relationships with customers or potential customers. CRM system for the contact center may include customizable client cards, filter construction, blacklist features, etc. Learn more about call center CRM system

D section


The sheet with detailed data about call center operations, such as calls per day or per hour that includes many important metrics and helps to control call center activity and performance.

Delayed Call

A call that is placed in the queue because the agent cannot answer it immediately, or there are no agents available.

Dialer (dialler)

Software platform that automatically dials phone numbers from the lists loaded in advance for outbound campaigns. Apart from dialing, it can report on the outcomes of calls and reorganize unanswered call attempts in order to be retried automatically at a later time/date.

Power dialer

A dialing mode that allows making calls one by one and routes them to agents as soon as they are answered. If it reaches voicemail or a busy number it moves to the next number on the list. The Power dialer dials only when an agent is available, thus removing the risk of abandoned calls.

Progressive dialer

See Power dialer.

Predictive dialer

A dialing mode that allows making some number of calls at once based on an intelligent algorithm that also places calls when an agent is about to become available, thus reducing their idle time. Predictive dialer works best for teams of 5+ agents. Read more about predictive dialers

Dual-Tone Multifrequency (DTMF)

This is a signaling system where pairs of audio frequencies are sent to represent digits on the telephone keypad. It is also known as Touchtone (an AT&T trademark).

DID (Direct Inward Dialing)

The algorithm that allows you to get a set of phone numbers that work through one line inside your organization. DID is always used with the PBX system to make it easier to manage call operations. 

E section

Erlang Calculator

A simple calculator in Excel spreadsheet format. It will allow you to work out both the raw and total number of agents for any call volume, as well as the Predicted Service Level for a provided number of agents and the probability that a call has to wait. 

Employee engagement

The rate that shows how interested and engaged are employees in their work. Strongly depends on motivation, workforce management, and work environment. 


The situation where the customer asks to transfer the call to the agent’s boss or higher manager because of low quality of service or the agent’s inability to solve the problem. Sometimes, escalation is initiated by the agent if he feels a lack of knowledge or skills. 

F section

FCR – First Call (Contact) Resolution

First Call (Contact) Resolution is a percentage measure that shows how many customer queries the call (contact) center answered during the first contact. Learn more about how to improve FCR


Analysis and prediction of future call volume and needed number of operators to handle it. 

Full-time equivalent

The rate to count how many part-time workers are needed to handle the same amount of work that is handled by a full-time worker.

H section

Handled Calls

All calls that were handled by operators or peripheral equipment, except for ones that were abandoned or received busy signals.

Handling Time

The amount of time spent to handle a particular call. It includes both talk time and after-call work.

I section

Inbound calls

Calls that are originated by the customers or leads to reach you with questions or service requests. 

Interexchange Carrier (IXC)

The term to determine any carrier that provides service in several areas. 

ICR (Intelligent Call Router)

This is an intelligent telecommunications network service that uses real-time information from the call center's ACD to provide details on queuing and agent availability across a virtual call center network.

Idle Time (Available Time)

A time when agents are ready and waiting to handle calls. During idle time, a logged-in agent is not engaged in talking to a customer or in after-call work.

IVR (Interactive Voice Response)

A system that interacts with customers when they ring a call center. It allows them to contact a company through either touchtone or speech recognition. Typically the IVR asks customers to press some button on their telephone keypad ("press one for this", "press two for that") to choose a service or information they want. It also routes them to the most appropriate agent if necessary. In some cases, IVR can ask a customer to enter some information through their telephone keypad - for instance, to type some digits of an account number. Learn more

K section

Key Performance Indicator (KPI)

Key performance indicators (KPIs) are also known as metrics. They measure various aspects of business and processes' performance. Call center KPIs may include Average Handling Time, Average Speed of Answer, First Call (Contact) Resolution, etc.

Knowledge Management System (Knowledge Base)

A desktop application that serves as a source of information for agents while they are answering customer inquiries. Agents may have to handle a large range of inquiries or the responses may change regularly, so the Knowledge Management System acts as a single source of content for the center to use.

L section

Lifetime Customer Value (LCV)

The entire value of the client from his first interaction with the company until the last one.

Local Area Network (LAN)

The network that links computers in a precise area or building, such as an office or coworking. 

Load Balancing

Balancing traffic between several destinations (two or more).

Logged On

An agent's status in the system when they made their presence known but may or may not be ready to receive calls.

Longest Waiting Agent (Longest Available agent)

This is a method of call distribution when calls are routed to the agent who has been sitting idle the longest. As a queue moves Longest Waiting Agent becomes the next Available Agent.

Lost Calls

Any inbound calls when a caller wasn't connected to either an advisor or an answering service.

M section


The process of listening to the agents' calls in order to maintain quality. See also: Call Monitoring Modes.

Multichannel Contact Center

The contact center with several communication channels, such as email, messengers, or social media. Never confuse it with the omnichannel contact center. 

N section

Nuisance Call

An unwanted or unwelcome call that troubles the recipient.

Net promoter score (NPS score)

The metric that varies from +100 to -100 and shows customer loyalty to the company. 

O section

Outbound Dialing Campaign

A dialing campaign in which agents are tasked to place calls to make sales, generate leads, market a brand, or perform research.


The sharing of some call center's business tasks with a third-party company. The outsourcer can handle both inbound and outbound campaigns on your behalf placing calls of different types - telemarketing, customer service, technical helpdesk, debt management, and many more. Also known as Business Process Outsourcing (BPO). 

Off-phone activity

Any activity done by the agent, that doesn’t relate to communication with customers. 

Omnichannel contact center

The contact center that offers multiple communication channels, and allows customers to switch between channels without losing conversation progress. 

P section

PBX (Private Branch Exchange)

A telephone system placed on the customer's website that handles inbound and outbound calls. PBX can have ACD functionality. Also known as private automatic branch exchange (PABX).

Post call processing

The amount of time spent after every successful contact to finish all necessary after-call activities, like filling the script, and so on.

Q section

Queue Time

The amount of time a customer spends in the queue waiting for an available agent.

Quality Assurance

The procedure of evaluating agent performance by using special quality assurance scorecards. Is used to identify mistakes, imperfections, and improvement areas for future training. 

Quality monitoring (QM)

The technology that tracks agent performance and service level compliance across all stages of the customer journey. 

Quality of Service (QoS)

The system to manage data streams and prioritize those that are more crucial for customers. In the call center industry, voice data streams(calls) are always more prioritized. 

R section

Real-Time Management

Making changes in terms of staffing and thresholds in the systems and network responding to current queue conditions.

Received Calls

Calls that are detected and seized by a system. These are both calls answered by agents and abandoned ones.

Remote Agents

Agents that work remotely from a location other than a traditional call center, usually from home. Learn more about remote call center

Request for information (RFI)

Company's official request to the Service Provider Company regarding the list of options and features that are included in the product.

Request for proposal (RFP)

RFP is the request that almost always follows the RFI. This is the request for a ready-for-service solution that would meet the business needs and requirements which are described in the RFP. 

Response Time

The time of the contact center's response to transactions that do not have to be handled immediately (for instance, emails).

Return on Investment (ROI)

The main business metric that shows how much profit you get from your investments. 

S section

SaaS – Software as a Service

An item of software or a system that is (remotely) delivered by a provider to a subscriber or user base.

Skills-Based Routing

The type of routing that links customers to agents depend on agents’ skills and experience and its relevance to the customer’s requests. 

Schedule Adherence

The metric that shows how agents follow the requirements of their schedule. 

Shrinkage Rate

The rate to determine the amount of time when agents are paid but don’t handle customer communications. 

Script (call script)

A written guide or questionnaire that agents use while handling calls. Check the call scripting software


If your company provides a self-service, customers can complete a transaction or have their query answered without involving any member of the customer service team.

Session Initiated Protocol (SIP)

A signaling system that allows you to integrate a whole range of applications including voice, data, video, pictures, and online games. With the help of SIP, users can switch between one mode and another. For example, they may play games online through a mobile phone and be able to use a “push to talk” button.

Service Level

Service Level is measured as the percentage of calls answered within a specified period defined by the business.

Service Level Agreement

The kind of agreement between the agents and management determines the minimum level of service provided by the agents. For instance, it may contain such parameters as the minimal number of answered calls, the longest possible waiting time, and the maximum percentage of escalated calls. 


The technology to make calls using the web from personal computers, laptops, or smartphones. 

T section 

Total Cost of Ownership

The overall price of all purchases, operating costs, and other spending that is made by the business owners to set up and maintain the organization.

Text-to-speech (TTS)

The tool that transforms text into voice messages. 

U section

Unified communications

The overall system of the company's communication service, that includes voice, audio, video, and message communications. 

V section

Voice over Internet Protocol (VoIP)

The protocol that allows performing voice calls via the Internet without any geographical or other limitations. 

Voice authentication

The type of authentication by using the caller’s voice to get access to data and services.

Voice bot

The AI-powered bot that listens to customers and helps them by identifying their voice requests. 

W section

WFM (Workforce Management Tools)

These are software solutions designed to forecast call load, calculate staff requirements, make schedules and track the real-time performance of individuals and groups.

Workforce Optimization (WFO)

The model of management to reduce labor costs, and improve data accessibility, training processes, and other aspects of workforce management. 

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