if we define agnostic as believing one thing but knowing that you could be wrong then yes.
The most practical definition of agnosticism if your goal is differentiate it from atheism and theism is one of conviction or commitment of belief.A theist may not know if there is a god, but believes strongly that there is one.
A (strong) atheist may not know if there is a god, but believes strongly that there isn't one.
An agnostic does not know if there is a god, and therefore refuses to commit either way.
However, the act of non-committal means that there will be no worshipping or active believing being done of any gods (because that would be a form of commitment). That could be construed as weak atheism (no belief in gods).
If you want to stick with the true etymological definition, agnosticism is just the opposite of gnosticism, which is the belief that one possesses spiritual knowledge. Therefore, agnosticism would be the belief that one does
not possess spiritual knowledge. This is the definition you've been using throughout this thread, but you if you're going to use it then you have to understand that it's not a mutually exclusive state from either atheism OR theism.