Definition of ohmigod in English:
ohmigod
(also ohmygod)
exclamation ˌəʊmʌɪˈɡɒdˈəʊmʌɪɡɒd
North American informal Origin
1970s; earliest use found in The New York Times. Altered spelling of oh my god, apparently intended to represent a rapid or emphatic pronunciation. Compare earlier migod.