Толковый словарь английского языка Oxford English Reference - occur

v.intr. (occurred, occurring) 1 come into being as an event or process at or during some time; happen. 2 exist or be encountered in some place or conditions. 3 (foll. by to; usu. foll. by that + clause) come into the mind of, esp. as an unexpected or casual thought (it occurred to me that you were right). Etymology: L occurrere go to meet, present itself (as OB-, currere run)