occurrence

n. occurrence, happening, event

(n.)
Any incident or event; esp., one which happens without being designed or expected; as, an unusual occurrence, or the ordinary occurrences of life.
  

(n.)
A coming or happening; as, the occurence of a railway collision.
  

Noun
1. an event that happens
(synonym) happening, natural event
(hypernym) event
(hyponym) accompaniment, concomitant, co-occurrence
2. an instance of something occurring; "a disease of frequent occurrence"; "the occurrence (or presence) of life on other planets"
(hypernym) presence
(hyponym) allopatry