A period of time during which a group of people meet to do something.
A session can be for learning, talking, or making decisions. It is a planned time for doing something specific.
Examples:
We have a reading session at the library.
The music session is at 3 o'clock.
The session for playing games is on Saturday.
I love the session when we eat cake!
The session for building the biggest tower lasted all day.
In the session, we all sang together.