A session is the period of time a customer spends browsing your site. 

Ometria counts and closes a visit session after 30 minutes of inactivity.

E.g. If a contact visits your site, browses, then takes no further action, Ometria counts the session once 30 minutes has passed since their last click. 

If the user is inactive (no clicks) for 32 minutes, then returns and performs an action (clicking a link on your site), this counts as a second visit session.