From Longman Dictionary of Contemporary Englishnot a/not onenot a/not onenot any person or thing Not one of the students knew the answer. There wasn’t a cloud in the sky. Not a single person said thank you. → not
Examples from the Corpus
not a/not one• But not a one of them was able to stay awake through the night, so they all were beheaded.• This change is not a one way process. 