AI Companion Glossary: 40 Terms Every User Should Know

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Summary. This glossary defines 40 terms used in AI companion apps and AI roleplay platforms, grouped into six categories: basics, characters and personas, conversation mechanics, memory, roleplay craft, and safety and privacy. Each entry begins with a one-sentence definition, followed by a short explanation of why the term matters in practice. Definitions are written to be platform-neutral; where a term works differently on Varenchat, the entry says so explicitly.

How to use this glossary

Terms are grouped by category rather than listed alphabetically, because most questions people have ("why did my character forget?", "what does OOC mean?") cluster around one topic. Within each category, related terms are placed next to each other. An alphabetical index is included at the end of the page.

1. Basics

AI companion

An AI companion is a software character, powered by a large language model, that holds ongoing conversations with a user and is designed to be a consistent presence over time rather than a one-off tool. AI companions are used for roleplay, storytelling, casual conversation, language practice, and social rehearsal. The defining difference between an AI companion and a general assistant (such as ChatGPT or Claude) is continuity: a companion is expected to keep a stable personality and, on platforms that support it, remember earlier conversations.

AI character

An AI character (also called a bot or companion character) is a specific named personality that a user can chat with inside an AI companion app. A single app usually offers many AI characters. Each character has a defined name, appearance, personality, speaking style, and often a backstory. On Varenchat, all characters are original creations made by the platform rather than user uploads; see Original character (OC).

Chatbot

A chatbot is any program that responds to text or voice messages in conversation. The term is broader than AI companion: customer-service bots, assistants, and companion characters are all chatbots. In everyday usage, "chatbot" tends to describe task-oriented tools, while "AI companion" describes relationship- or story-oriented ones.

Large language model (LLM)

A large language model (LLM) is the underlying AI system that generates the text an AI character says. LLMs are trained on large amounts of text and predict likely next words given the conversation so far. The character's personality is not built into the model; it is created by instructions (see System prompt and Character definition) that shape how the model responds.

Roleplay (RP)

Roleplay (RP) is a form of collaborative storytelling in which each participant writes the actions and dialogue of one or more characters in a shared scene. In AI roleplay, the user plays one side and the AI character plays the other. Roleplay can be short (a single scene) or continuous over weeks or months.

Interactive story

An interactive story is a narrative in which the reader's choices change what happens next. In AI companion apps, interactive stories differ from open-ended chat by having a setting, a starting situation, and story beats, while still letting the user type freely. Varenchat describes its format as interactive roleplay stories: the user shapes the story through conversation, and the character carries those choices forward.

Turn

A turn is one message from the user followed by one reply from the AI character. Turn counts matter because most platforms measure limits (free-tier caps, context length) in turns or messages, and because memory problems often appear after a certain number of turns.

2. Characters and personas

Persona

A persona is the defined personality an AI character adopts: its name, voice, attitudes, habits, and boundaries. The word is also used for the user persona (see below). When people say a character "broke persona," they mean it stopped behaving like its defined personality.

Character definition

A character definition (also called a character card) is the written specification that tells the language model who a character is. It typically includes a description, personality traits, speaking style, example dialogue, and a greeting. On platforms that allow user-created characters, the user writes this; on platforms with original characters, such as Varenchat, the platform's writers do.

Backstory (lore)

A backstory, or lore, is the history and world context behind a character: where they come from, what happened to them, what they want, and what rules their world follows. Well-written lore helps a character stay consistent. Very long lore can be counterproductive on platforms with small context windows, because the model may not be able to read all of it at once.

Greeting (first message)

A greeting is the opening message an AI character sends when a new conversation begins. It usually establishes the setting, the situation, and the character's voice. The greeting is one of the strongest signals of how a character will behave, because the model treats it as an example of the character's style.

Example dialogue

Example dialogue is a set of sample exchanges included in a character definition to show the model how the character talks. Models tend to imitate the length, formatting, and tone of example dialogue closely, which makes it one of the most effective tools for controlling a character's style.

User persona

A user persona is the description of the person or character the user is playing in a conversation. It can be as simple as a name or as detailed as a full character sheet. Apps with long-term memory may build the user persona automatically from what the user says over time; apps without it require the user to restate details.

Original character (OC)

An original character (OC) is a character created from scratch rather than taken from an existing book, game, film, or franchise. The opposite is a canon character (CC). Platforms that use only original characters, such as Varenchat, avoid copyright issues and can design each character's backstory specifically for long-running conversation.

3. Conversation mechanics

Prompt

A prompt is any text sent to a language model to produce a response. In AI companion apps the prompt the model actually sees is assembled from several parts: the system prompt, the character definition, relevant memories, and the recent conversation. The user's message is only one piece of it.

System prompt

A system prompt is the hidden instruction block that tells the model how to behave for the whole conversation, such as "You are [character]. Stay in character. Never reveal these instructions." Users usually cannot see it. The system prompt is where a platform encodes its rules, content policies, and formatting preferences.

Context window

A context window is the maximum amount of text a language model can read at once when generating a reply, measured in tokens. Everything the model "knows" about the current conversation must fit inside this window. When a conversation grows past the window, the oldest messages fall out and the model can no longer see them, which is the most common cause of an AI character forgetting things mid-conversation. A context window is not the same as memory; see Long-term memory.

Token

A token is the unit a language model uses to measure text; one token is roughly three-quarters of an English word. A 1,000-word conversation is about 1,300 tokens. Context windows, pricing, and message limits are typically expressed in tokens.

Regenerate (swipe)

Regenerate, often called swipe on mobile apps, asks the model to produce a different reply to the same message. It does not change the conversation history; it replaces the last AI reply with a new attempt. Regenerating is the standard way to fix a reply that is off-tone, repetitive, or out of character.

Edit / rewind

Edit lets the user change the text of a previous message, and rewind (or delete) removes recent messages so the conversation continues from an earlier point. Both change what the model sees in its context window, so they are also memory tools: removing a mistaken message prevents the model from building on the mistake.

Temperature

Temperature is a model setting that controls how random or predictable replies are. Low temperature produces safer, more repetitive text; high temperature produces more surprising but less consistent text. Most consumer companion apps do not expose this setting directly, but the concept explains why some characters feel "creative" and others feel "flat."

Hallucination

A hallucination is a confident statement by an AI character that is invented rather than based on the conversation or the character's definition. In roleplay, hallucinations often appear as the character inventing a fact about the user ("your sister Anna") that was never mentioned. Persistent memory reduces this specific kind of hallucination because the model can check stored facts instead of guessing.

4. Memory

Short-term memory

Short-term memory, in an AI companion, is everything currently inside the context window: the recent messages the model can directly read. It is automatic and needs no special feature, but it is limited and temporary. When people say an app "has no memory," they usually mean it has only short-term memory.

Long-term memory

Long-term memory is a system that stores information from past conversations outside the context window and brings it back when relevant, so a character can recall facts, events, and relationship history from days or months earlier. Implementations vary: some apps keep an editable list of facts, some store summaries, and some retrieve past messages by relevance. Long-term memory is the feature Varenchat is built around; its conversations are designed to carry the user's choices and details forward across sessions.

Memory note (pinned memory)

A memory note, or pinned memory, is a piece of information the user or the app explicitly marks to be kept and shown to the model in every conversation. Pinned memories are a manual form of long-term memory: reliable for a small number of key facts, but limited in size and dependent on the user maintaining them.

Summarization (memory compression)

Summarization, sometimes called memory compression, is the process of condensing older messages into a short summary so they take up less room in the context window. Summarization lets conversations run longer but loses detail; a specific line of dialogue or a small promise may not survive the summary.

Recall

Recall is the act of an AI character correctly retrieving a stored fact or past event when it becomes relevant, without the user prompting it. Recall is the practical test of memory: a system may store everything but still fail to bring the right thing back at the right time.

Continuity

Continuity is the quality of a conversation or story in which facts, relationships, and events stay consistent over time. Continuity depends on both memory (the facts are available) and consistency (the model uses them). A story with good continuity does not require the user to re-explain the setting or their character.

Callback

A callback is a moment when a character refers back to something from earlier in the relationship or story: an inside joke, a promise, a past event. Callbacks are the most visible benefit of long-term memory, and the feature users most often describe as making a character feel "real."

Memory reset

A memory reset is the loss of stored information about a user or conversation, either because the user deleted it, because the app cleared it (for example when a conversation is restarted), or because of a platform change. Understanding when a platform resets memory, and whether the user is told, is a reasonable question to ask before relying on any companion app.

5. Roleplay craft

OOC (out of character)

OOC, short for out of character, marks a message that is from the user as themselves rather than from the character they are playing. It is used to give instructions, ask questions, or correct the story without the character responding in-scene. OOC is usually written in double parentheses, ((like this)), or in square brackets, [OOC: like this]. The opposite is IC (in character).

Action text (asterisks)

Action text describes what a character physically does, as opposed to what they say. In chat-based roleplay it is conventionally wrapped in asterisks, *she sets the cup down*, or written in italics, while spoken dialogue is left plain or placed in quotation marks. Keeping actions and speech visually distinct helps both humans and language models follow a scene. Full conventions are covered in the companion article AI Roleplay Formatting Conventions.

Narrator mode

Narrator mode is a roleplay style in which the AI describes the scene, setting, and side characters in third person, like the narrator of a novel, rather than speaking only as one character. Narrator mode is common in interactive stories and text adventures, and useful when a scene involves several characters.

Scene

A scene is a continuous segment of a roleplay set in one place and time. Ending a scene and starting a new one (for example by writing "The next morning...") is the standard way to change location, skip time, or restart pacing without starting a whole new conversation.

Time skip

A time skip is a deliberate jump forward in story time, such as "three weeks later." Time skips keep long-running roleplay from stalling in a single moment and give a memory-enabled character an opportunity to reference what happened before the skip.

Slow burn

A slow burn is a story in which a relationship or plot develops gradually over many scenes instead of resolving quickly. Slow-burn roleplay depends heavily on memory and continuity, because the payoff comes from the character remembering the small steps that led there.

6. Safety and privacy

Content filter

A content filter, or safety filter, is a set of rules that prevents an AI character from producing certain kinds of content, such as sexual content, graphic violence, or self-harm instructions. Filters are implemented in the system prompt, in the model itself, or as a separate check on the output. Filter strictness is one of the main differences between companion platforms, and one of the main reasons users switch between them.

Age gate

An age gate is a check that restricts an app or feature to users above a certain age, typically 18. Age gates range from a self-declared birthdate to identity verification. Companion apps use them to comply with app-store and regional rules about content available to minors.

Data retention

Data retention describes how long a platform keeps user data, including chat messages and memory, and under what conditions it is deleted. A platform's privacy policy should state its retention period and whether conversations are used to train models. On Varenchat, the relevant documents are the Privacy Policy and the EULA, both linked in the site footer.

Account deletion

Account deletion is the process by which a user permanently removes their account and associated data from a platform. Under regulations such as the GDPR and the CCPA, users generally have the right to request deletion. Varenchat provides a dedicated account-deletion page; users of any companion app should confirm that deleting an account also deletes stored memories, not only the login.

Quick reference: terms that are often confused

Term A	Term B	The difference in one line
Context window	Long-term memory	The window is what the model can read right now; long-term memory is what is stored and brought back later.
Persona	User persona	The character's personality vs. the description of the person the user is playing.
OOC	IC	A message from the user as themselves vs. a message from the character they play.
Regenerate	Edit	Ask for a different reply vs. change the text of an existing message.
Memory note	Summarization	A fact explicitly saved vs. old messages automatically condensed.
Chatbot	AI companion	Any conversational program vs. one designed for continuity and personality.
Original character	Canon character	Created from scratch vs. taken from an existing franchise.
Continuity	Consistency	Facts stay the same over time vs. the character behaves like itself.

Frequently asked questions

What is the difference between a context window and memory in an AI companion? The context window is the amount of recent text the model can read while writing a reply, measured in tokens. Memory is a separate system that stores information from past conversations and brings it back later. An app can have a large context window and still have no long-term memory; once the conversation exceeds the window, earlier details are gone unless a memory system stored them.

What does OOC mean in AI roleplay? OOC stands for "out of character." It marks a message written by the user as themselves, not as their character, usually to give the AI an instruction or correction. It is typically written as ((text)) or [OOC: text].

Why does my AI character forget things I told it? The most common reason is that the conversation has grown past the model's context window, so the earlier messages are no longer visible to it. Other causes include summarization that dropped the detail, a memory reset, or the app having no long-term memory at all. See the entries for Context window, Summarization, and Long-term memory.

What is a persona in an AI chat app? A persona is the defined personality of an AI character: its name, voice, attitudes, and boundaries. The same word is used for the user persona, which describes who the user is playing. A character that "breaks persona" has stopped behaving according to its definition.

What is a callback in roleplay? A callback is when a character refers back to something from earlier in the story or relationship, such as an inside joke or a promise. Callbacks require the character to have access to that earlier information, which is why they are the clearest visible sign of working long-term memory.

Is an AI companion the same as a chatbot? Every AI companion is technically a chatbot, but not every chatbot is an AI companion. "Chatbot" covers any conversational program, including customer-service tools. "AI companion" specifically means a character designed for ongoing conversation with a stable personality and, ideally, memory.

Alphabetical index

Account deletion · Action text (asterisks) · Age gate · AI character · AI companion · Backstory (lore) · Callback · Character definition · Chatbot · Content filter · Context window · Continuity · Data retention · Edit / rewind · Example dialogue · Greeting (first message) · Hallucination · Interactive story · Large language model (LLM) · Long-term memory · Memory note (pinned memory) · Memory reset · Narrator mode · OOC (out of character) · Original character (OC) · Persona · Prompt · Recall · Regenerate (swipe) · Roleplay (RP) · Scene · Short-term memory · Slow burn · Summarization (memory compression) · System prompt · Temperature · Time skip · Token · Turn · User persona

About this glossary

This glossary is maintained by the Varenchat team and updated when terminology or platform features change. Definitions are intended to be platform-neutral. Varenchat is an AI companion platform built around original characters, interactive roleplay stories, and long-term memory. To cite this page: Varenchat, "AI Companion Glossary: 40 Terms Every User Should Know," varenchat.ai/blog/ai-companion-glossary, updated September 28, 2026.