episode

Concise Oxford English Dictionary © 2008 Oxford University Press:
episode/ˈepɪsəʊd/

▶noun

• 1 an event or a sequence of events.

  ■ a finite period in which someone is affected by an illness.

• 2 each of the instalments into which a serialized story or radio or television programme is divided.

• 3 Music a passage containing distinct material or introducing a new subject.

  ■ a section between two choric songs in Greek tragedy.

– origin C17: from Gk epeisodion, neut. of epeisodios ‘coming in besides’.