Is no one one word

Answer 1

It can be one word or two words. Both ways are right. Cannot and can not. Or can't for short.

While both forms are acceptable, some dictionaries recognize only the combined form, except when the "not" is not part of another construction (e.g. not only, not do something). In short, cannot cannot be considered wrong, while can not can.

Answer 2

The correct way to write it is nowhere. Therefore your answer is one word.

An example sentence is "we had nowhere to go".

Answer 3

No it is two words.