Reference
Call Center Glossary
38 plain-language definitions for the terms agents, supervisors, and operations managers use every day — from ACD and AHT to WebRTC and WFM. Each definition includes the industry benchmark or statistic where available.
Maintained by the Nectar Desk team · Last updated June 2026
A
- ACD (Automatic Call Distributor)See feature →
- A telephony system that automatically routes incoming calls to the most appropriate agent or queue based on pre-configured rules such as skills, availability, or priority. ACD is the backbone of inbound call center operations.
- AHT (Average Handle Time)
- The average total duration of a customer interaction, including hold time, talk time, and after-call work (wrap-up). AHT is a primary efficiency KPI; the cross-industry median is approximately 6 minutes.
- ANI (Automatic Number Identification)
- A feature that transmits the caller's phone number to the receiving system before or during the call. ANI enables screen pop, caller history lookup, and priority routing.
- Auto DialerSee feature →
- Software that automatically dials a list of phone numbers and connects answered calls to available agents. Types include preview, progressive, power, and predictive dialers.
- ASR (Automatic Speech Recognition)
- AI technology that converts spoken audio to text in real time, enabling voice bots and virtual agents to process natural language from callers. Modern cloud ASR systems achieve over 95% word accuracy in controlled telephony environments. ASR is the input layer of every AI voice bot pipeline — the text it produces is then passed to NLU for intent classification.
- AI Voice BotSee feature →
- An automated phone agent that combines ASR (speech to text), NLU (intent classification), LLM (response generation), and TTS (text to speech) to conduct spoken conversations without a human agent. AI voice bots resolve 40–65% of calls without escalation (Opus Research) and replace or augment traditional DTMF-driven IVR menus.
B
- Barge-inSee feature →
- A supervisor capability that allows a manager to join an active agent call as a full participant, audible to both the agent and the customer. Used for escalation, coaching, and real-time quality correction. Compare with Whisper, where only the agent hears the supervisor.
- Blended Agent
- An agent who handles both inbound and outbound contacts — switching between receiving incoming calls and making outbound calls as queue volumes dictate. Blended models maximize agent utilization.
C
- Call Abandon Rate
- The percentage of inbound callers who disconnect before reaching an agent. Industry benchmark is below 5%; rates above 8% indicate understaffing or queue mismanagement.
- Call Queue
- A virtual waiting line that holds inbound callers until an agent becomes available. Queues can be configured with priority rules, music on hold, estimated wait time announcements, and overflow routing.
- Call RecordingSee feature →
- The capture and secure storage of audio (and sometimes screen) from agent interactions for compliance, quality assurance, and coaching purposes. 85% of contact centers cite call recording as their most-used QA tool.
- Call WhisperSee feature →
- A coaching feature allowing a supervisor to speak to an agent during a live call without the customer hearing. Used to guide new agents in real time without disrupting the customer experience.
- CLI (Caller Line Identification)
- The telephone number of the calling party transmitted to the receiving end before the call is answered. Widely used in European telephony (equivalent to ANI in North America). CLI data feeds screen pop and caller history systems, and allows businesses to display a local number on outbound calls via outbound CLI masking.
- CRM (Customer Relationship Management)See feature →
- Software that centralizes customer data, interaction history, deal pipeline, and communication records. Native CRM integration is standard in modern call center platforms — every call, SMS, and chat log is automatically written back to the customer record. Nectar Desk includes a built-in CRM and integrates natively with HubSpot, Salesforce, Pipedrive, Zoho, and 100+ others.
- CSAT (Customer Satisfaction Score)
- A post-interaction survey metric, typically a 1–5 or 1–10 scale question asking customers how satisfied they were with the interaction. Industry average CSAT for voice is 77%; top performers reach 85%+.
- CTI (Computer Telephony Integration)See feature →
- Technology that links a phone system to a computer or software application, enabling features like screen pop, click-to-call, and automatic call logging in a CRM. CTI reduces AHT by 15–20 seconds per call on average.
- Conversational AI
- AI systems capable of sustaining multi-turn, human-like dialogues in text or voice. Unlike single-turn chatbots, conversational AI maintains context across the conversation, handles interruptions, and dynamically adjusts responses. The global conversational AI market is projected to reach $18.4 billion by 2026 (MarketsandMarkets).
- Containment Rate
- The percentage of inbound calls or conversations fully resolved by an AI voice bot or self-service channel without escalation to a live agent. Opus Research benchmarks show 40–65% containment for well-configured AI voice bot deployments; initial deployments without tuning typically start at 30–40%. Containment rate is the primary ROI metric for AI voice bot investments.
D
- Disposition CodeSee feature →
- A classification tag that agents apply to a call at the end of each interaction to record the outcome (e.g., 'Sale Closed', 'Callback Scheduled', 'No Answer'). Disposition codes feed reporting and workflow automation.
- DNIS (Dialed Number Identification Service)
- A feature that identifies which telephone number a caller dialed, even when multiple numbers share the same trunk or agent group. DNIS allows a single call center to run multiple brands or campaigns and route calls — or play different greetings — based on the number dialed, without requiring separate phone lines.
- DTMF (Dual-Tone Multi-Frequency)See feature →
- The touch-tone telephone signaling standard that encodes keypad inputs (digits 0–9, * and #) as pairs of audio frequencies. DTMF is the interaction mechanism of traditional IVR systems — press 1 for billing, press 2 for support. AI voice bots replace DTMF-driven IVR menus with natural language input, removing the need for callers to memorize menu trees.
E
- Entity Extraction
- The process of pulling specific structured data — account numbers, dates, product names, dollar amounts, addresses — from natural language utterances. Entity extraction works alongside intent detection: the intent tells the system what to do; the entity provides the data needed to do it. For example, in 'cancel my order from last Tuesday', 'cancel' is the intent and 'last Tuesday' is the date entity.
F
- FCR (First-Call Resolution)
- The percentage of customer issues fully resolved on the first contact without a callback or escalation. FCR is the highest-correlation metric for CSAT and operating cost — every 1% FCR improvement reduces costs by 1% (SQM Group).
I
- IVR (Interactive Voice Response)See feature →
- An automated phone system that interacts with callers through a menu of voice prompts or keypad inputs, routing them to the correct department or providing self-service options. Well-configured IVRs deflect 30–40% of tier-1 contacts.
- Intent DetectionSee feature →
- The process of identifying a caller's goal from their natural language input — for example, classifying 'I need to cancel my order' as a Cancel Order intent. Intent detection is the routing core of every voice bot: the correct intent must be identified before any action can be taken. High-performing enterprise systems achieve over 96% intent recognition accuracy.
K
- Knowledge BaseSee feature →
- A structured repository of articles, guides, and FAQs that agents and customers use to find answers. Integrated knowledge bases reduce AHT and support FCR by giving agents instant access to verified information during calls.
L
- Live ChatSee feature →
- A real-time text-based communication channel embedded in a website or app. Live chat achieves 83.1% average CSAT — among the highest of any support channel — and increases purchase conversion rates 3×.
- LLM (Large Language Model)
- A deep learning model trained on massive text corpora that generates human-like text by predicting the next token. GPT-4, Claude, and Gemini are LLM-class models. In AI voice bots, LLMs generate contextually accurate, on-brand responses grounded in a call center knowledge base. Key enterprise considerations include context window size, hallucination risk, and the need for grounding and guardrails.
N
- NPS (Net Promoter Score)
- A loyalty metric derived from the question 'How likely are you to recommend us to a friend or colleague?' scored 0–10. NPS segments respondents into Promoters (9–10), Passives (7–8), and Detractors (0–6). Score = % Promoters − % Detractors.
- NLP (Natural Language Processing)
- The umbrella AI field covering all machine interpretation and generation of human language — including speech recognition, text understanding, translation, and language generation. NLP encompasses both NLU (understanding intent) and NLG (generating responses). All modern AI voice bots and conversational AI systems are built on NLP foundations.
- NLU (Natural Language Understanding)See feature →
- A sub-field of NLP focused on extracting structured meaning from natural language — classifying caller intent (e.g. 'make a payment', 'check order status') and extracting named entities (account numbers, dates, product names). NLU is the routing core of every AI voice bot: it determines what the caller wants so the system can take the right action.
O
- Omnichannel
- A contact center strategy that unifies customer interactions across all channels — voice, email, SMS, chat, social, and messaging apps — in a single agent workspace with a shared conversation history. Companies with omnichannel strategies retain 89% of customers vs. 33% for single-channel.
- Outbound Calling Campaign
- A structured effort to proactively contact a list of leads, customers, or prospects by phone. Campaigns are managed through auto-dialers and can be configured with call ratios, schedules, machine detection, and voicemail drop.
P
- Power Dialer
- A type of auto dialer that dials one number at a time per available agent, connecting the agent the moment the call is answered. Less aggressive than predictive dialers; minimizes dropped calls and compliance risk.
- Predictive DialerSee feature →
- An advanced auto dialer that simultaneously dials multiple numbers per agent using algorithms to predict agent availability. Predictive dialers increase agent talk time from ~15 minutes per hour to 40–50 minutes, reducing idle time by up to 85%.
- Progressive Dialer
- A dialer that automatically dials the next number from a list only when an agent signals readiness. Offers more control than predictive dialing with fewer dropped calls, making it suitable for compliance-sensitive campaigns.
Q
- QA (Quality Assurance)See feature →
- The systematic process of reviewing recorded or live interactions to evaluate agent performance against defined scoring rubrics. QA programs typically sample 5–10% of calls and use findings to guide coaching and training.
R
- Ring GroupSee feature →
- A configured group of agents whose phones ring simultaneously or in sequence when a call arrives. Ring groups ensure calls are answered quickly even if individual agents are unavailable.
S
- Screen Pop
- The automatic display of a customer record or relevant information on an agent's screen at the moment a call connects, drawn from CRM or database lookup via ANI or CTI. Screen pop reduces AHT by 15–20 seconds per interaction.
- SIP (Session Initiation Protocol)
- The signaling protocol that sets up, manages, and terminates multimedia communication sessions — including voice and video calls — over IP networks. SIP trunking replaces physical phone lines, connecting a cloud call center to the public telephone network (PSTN) over the internet. It is the infrastructure layer beneath all VoIP-based call center software.
- Skills-Based RoutingSee feature →
- An ACD configuration that matches inbound contacts to agents whose specific skill profiles (language, product expertise, account tier) best fit the caller's need. Skills-based routing increases FCR and reduces repeat contacts.
- SLA (Service Level Agreement)
- A commitment to answer a defined percentage of contacts within a set timeframe — the most common standard being 80% of calls answered within 20 seconds (80/20). SLA is the primary scheduling and staffing target for inbound operations.
- Sentiment Analysis
- Real-time classification of a caller's emotional state — positive, neutral, or negative — from voice tone, word choice, or text. In call centers, sentiment analysis triggers automatic escalation when a caller exhibits frustration or distress, preventing churnable interactions from being mishandled by an AI bot or an unprepared agent.
T
- TTS (Text-to-Speech)
- AI technology that converts written text to natural-sounding spoken audio. Neural TTS systems from major cloud providers are indistinguishable from human voice in over 90% of blind listening tests. TTS is the output layer of every AI voice bot pipeline — it speaks the response generated by the LLM back to the caller.
V
- VoIP (Voice over Internet Protocol)
- Technology that transmits voice calls as data packets over an internet connection rather than traditional telephone lines. VoIP delivers 40–80% cost savings versus landlines and underpins all modern cloud call center platforms.
- Voicemail DropSee feature →
- A feature that lets agents leave a pre-recorded voicemail message at the press of a button when a call reaches voicemail, without waiting for the beep or recording manually. Increases agent productivity by up to 400% on outbound campaigns.
W
- Warm TransferSee feature →
- A call transfer method where the transferring agent speaks with the receiving agent before introducing the customer, passing context and background. Warm transfers reduce repeat contacts by 39% compared to blind (cold) transfers.
- WebRTC (Web Real-Time Communication)
- An open browser standard that enables voice, video, and data communication directly within a web browser — no plugin or installed software required. Modern cloud call center platforms use WebRTC to power the agent softphone, allowing agents to handle calls from any browser on any device with a stable internet connection.
- WFM (Workforce Management)
- The process and software used to forecast call volumes, schedule agents, track adherence, and optimize staffing levels in real time. WFM tools reduce over- and under-staffing costs and are essential at 50+ agent contact centers.
- Wrap-Up Time / ACW (After-Call Work)
- The time an agent spends on tasks directly related to a call after the customer hangs up — including entering notes, tagging dispositions, and updating CRM records. ACW is included in AHT calculations; automation tools reduce it by 30–50%.
Frequently Asked Questions About Call Center Terms
Direct answers to the most-searched call center terminology questions.
What is ACD in a call center?
ACD (Automatic Call Distributor) is a telephony system that automatically routes incoming calls to the most appropriate agent or queue based on skills, availability, or priority rules. ACD is the backbone of inbound call center operations and works alongside IVR to ensure callers reach the right agent without manual transfer.
What does FCR stand for in customer service?
FCR stands for First-Call Resolution — the percentage of customer issues fully resolved on the first contact without a callback or escalation. FCR is the highest-correlation metric for both CSAT and operating cost. Research by SQM Group shows every 1% improvement in FCR reduces operating costs by approximately 1%.
What is a predictive dialer and how does it work?
A predictive dialer is an auto-dialing system that simultaneously dials multiple numbers per agent using algorithms to predict when agents will become available. It connects agents only to answered calls, skipping busy signals, voicemails, and disconnected numbers. Predictive dialers increase agent talk time from roughly 15 minutes per hour to 40–50 minutes, reducing idle time by up to 85%.
What is IVR in customer service?
IVR (Interactive Voice Response) is an automated phone system that interacts with callers through voice prompts or keypad inputs to route them to the right department or offer self-service options. Well-configured IVR systems deflect 30–40% of tier-1 contacts, reducing agent workload and improving speed to resolution.
What is AHT (Average Handle Time) in a call center?
AHT (Average Handle Time) is the average total duration of a customer interaction, including hold time, talk time, and after-call work (ACW/wrap-up). The cross-industry median AHT is approximately 6 minutes. AHT is a core call center efficiency KPI — reducing it without sacrificing quality directly lowers cost per contact.
What is omnichannel support in a contact center?
Omnichannel support unifies customer interactions across all channels — voice, email, SMS, live chat, social media, and messaging apps — in a single agent workspace with a shared conversation history. Unlike multichannel support (where channels are siloed), omnichannel gives agents full context regardless of how a customer contacts the company. Research shows omnichannel companies retain 89% of customers vs. 33% for single-channel operations.
What is skills-based routing?
Skills-based routing is an ACD configuration that matches inbound contacts to agents whose skill profile — language, product expertise, account tier, or certification — best fits the caller's need. It reduces misdirected calls, increases First-Call Resolution, and minimizes the need for transfers or escalations.
What does SLA mean in a call center?
SLA (Service Level Agreement) in a call center is a commitment to answer a defined percentage of contacts within a set timeframe. The most widely used standard is 80/20 — answering 80% of calls within 20 seconds. SLA is the primary staffing and scheduling target for inbound operations and is typically monitored in real time on a supervisor dashboard.
See These Features in Action
Predictive dialers, IVR, screen pop, warm transfer — every term in this glossary is a built-in feature of Nectar Desk. Try them all, free for 7 days.