is a specific kind of: happening, natural event, occurrence, occurrent.

is a broader term that covers: associate | background.

derivation: co-occur, coincide, cooccur | accompany, attach to, come with, go with | accompanying, attendant, collateral, concomitant, consequent, ensuant, incidental, resultant, sequent | co-occurrent, coincident, coincidental, coinciding, concurrent, cooccurring, simultaneous.

is a specific kind of: simultaneity, simultaneousness.

is a broader term that covers: concomitance | overlap | contemporaneity, contemporaneousness | unison.

derivation: coincide, concur | co-occurrent, coincident, coincidental, coinciding, concurrent, cooccurring, simultaneous.