Numbaah

1. is a slangish nickname of "number" and "numbuh" it can also be used in a fanfiction story as a name.

2. a made up n00bish name that contains two a's.

3. is also a term Codename Kids Next Door characters use as a form of number.

Username: numbuhthreefan
Short name: Numbaah

Numb"er", Numb"aah", and Numb"uh"; are basically the same thing, only the end letters are changed.