n.
    - a period devoted to a particular activity:
 a training session.
 ▸a period of recording music in a studio.
 ▸informal a period of heavy or sustained drinking.
 - 
(often in phr. in session)
 a meeting of a deliberative or judicial body to conduct its business. 
▸a period during which such meetings are regularly held.
 - the part of a year or a day during which teaching takes place in a school or college.
 - the governing body of a Presbyterian Church.
 
 
  Derivative
  
  Etymology
  ME: from OFr., or from L. sessio(n-), from sess- (see sessile).