n.
   - an event or a sequence of events. 
▸a finite period in which someone is affected by an illness.
 - each of the instalments into which a serialized story or radio or television programme is divided.
 - Music  a passage containing distinct material or introducing a new subject. 
▸a section between two choric songs in Greek tragedy.
 
 
  Etymology
  C17: from Gk epeisodion, neut. of epeisodios ‘coming in besides’.