"aha" is the correct spelling.
Oho Aha
Oho! Aha!
aha, oho
The word "aha" is a verbal representation of an exclamation of understanding, realization or recognition.
Oho, Aha, Wow
No, it is not a noun. It is an interjection, an exclamation of triumph or realization.
Aha, oho, wow
wow, aha, oho
Oho! Aha! Wow!
Yay would be the correct word to use in this case.
In Spanish, "aha" does not have a specific meaning. However, if you are referring to "¡Aha!" (with an exclamation mark), it is an Interjection that expresses surprise, realization, or understanding.
Hey. Oh um boo haa