(1):

(n.) Hence, also, the time, period, or term during which a court, council, legislature, etc., meets daily for business; or, the space of time between the first meeting and the prorogation or adjournment; thus, a session of Parliaments is opened with a speech from the throne, and closed by prorogation. The session of a judicial court is called a term.

(2):

(n.) The act of sitting, or the state of being seated.

(3):

(n.) The actual sitting of a court, council, legislature, etc., or the actual assembly of the members of such a body, for the transaction of business.