ses·sion 
(sĕshən)
(sĕshən)n.
1.
a. A meeting of a legislative or judicial body for the purpose of transacting business.
b. A series of such meetings.
c. The term or duration of time that is taken by such a series of meetings.
2. The part of a year or of a day during which a school holds classes.
3. A period of time devoted to a specific activity: a recording session at a music studio; a login session that was disrupted by a power outage.
[Middle English, from Old French, from Latin sessiō, sessiōn-, act of sitting, from sessus, past participle of sedēre, to sit; see sed- in the Appendix of Indo-European roots.]
session·al adj.
session·al·ly adv.