Decoder. plain-English AI glossary

Turn

● Core

One message in a back-and-forth — one side saying one thing before the other responds.

Think of it like

A single volley in a tennis rally: one hit, then it’s the other player’s shot.

Example

A five-turn conversation is roughly five exchanged messages between you and the model.

How it actually works

Chat is modeled as a sequence of turns, each tagged with a role. The whole history of turns is what the model reads each time, so conversations grow token by token and eventually strain the context budget. Managing turns — trimming or summarizing old ones — is part of building chat apps.

For product teams

Long chats silently eat context; at some point old turns must be trimmed or summarized.

For engineers

A single role-tagged message unit; the granularity of conversation state.

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