1 happen, take place, arise, come about, befall, come to pass, chance, appear, surface, materialize, develop, become manifest, manifest itself, Colloq transpire, crop up, come off, turn up:
We reported to the police all that had occurred. What occurred to make you late this time?
2 occur to. dawn on, strike, hit, come to, suggest itself to, cross (someone's) mind, enter (someone's) head, be brought to (someone's) attention:
Has it occurred to you that she might not like opera?