Task
A task is a unit of work handed to an AI system and tracked through to completion, as opposed to a question that gets answered and forgotten.
What separates a task from a conversation is that it has a state. It is open, in progress, blocked on an approval, or done — and that state outlives the window it was created in. That is what lets work be delegated and checked later rather than supervised continuously.
It is also what makes an agent reviewable. A task carries what was asked, what the agent did, what it is waiting on and what it produced. Without that, a long-running agent is a conversation you have to re-read to find out whether anything actually happened.