session
Like a library checkout slip, it marks who you are and how long you stay signed in.
When you show a library card, you borrow books for a set time. A session is the period when a user is signed in and the app can prove who they are.
Each request to your database or server should include proof of identity, often a token, a small signed note that says "this is still Alex." Without a valid session, Row Level Security rules will block access.