occasion : Idioms & Phrases

• noun a formal event performed on a special occasion
  ceremony; observance; ceremonial.
  
  • a ceremony commemorating Pearl Harbor

WordNet

• adverb now and then or here and there
  once in a while; now and again; now and then; occasionally; at times; from time to time.
  
  • he was arrogant and occasionally callous
  • open areas are only occasionally interrupted by clumps of trees
  • they visit New York on occasion
  • now and again she would take her favorite book from the shelf and read to us
  • as we drove along, the beautiful scenery now and then attracted his attention

WordNet

• in case of need; in necessity; as convenience requires; occasionally. "That we might have intelligence from him on occasion,"

Webster 1913

• noun a vaguely specified social event
  function; affair; social function; occasion.
  
  • the party was quite an affair
  • an occasion arranged to honor the president
  • a seemingly endless round of social functions

WordNet

• to make prompt use of anything; not to let slip an opportunity.

Webster 1913