Omona (어머나) is a common exclamation originating from Korea, literally meaning “oh my god” or “oh my gosh”. In English context it is mostly used by K-pop fans, utilized when one wants to express surprise.
It may also be abbreviated into omo that can be repeated endlessly. A related expression is ayigo (아이고) that is more used for disappointment, disillusionment or frustration.
The phrase has been applied in the Korean language for centuries, to express the shock at an unexpected situation, similar to ayigo.
The rise of the expression’s popularity started in 2007 when it was featured in the K-pop song Tell me performed by Wonder Girls.
The one and only Urban Dictionary entry on the oriental word was created in 2008, shortly following the publishing of the Wonder Girls song.
Today it can mostly be found on k-pop sites, written with a latin alphabet, though with the Korean spelling a Korean speaker may find this word in several contexts.