| Noun | 1. | co-occurrence - an event or situation that happens at the same time as or in connection with another associate - any event that usually accompanies or is closely connected with another; "first was the lightning and then its thunderous associate" background - relatively unimportant or inconspicuous accompanying situation; "when the rain came he could hear the sound of thunder in the background" |
| 2. | co-occurrence - the temporal property of two things happening at the same time; "the interval determining the coincidence gate is adjustable" simultaneity, simultaneousness - happening or existing or done at the same time concomitance - occurrence or existence together or in connection with one another overlap - the property of partial coincidence in time contemporaneity, contemporaneousness - the quality of belonging to the same period of time unison - occurring together or simultaneously; "the two spoke in unison" |