A homophone is a word that sounds the same as another word but has a different meaning and spelling. While there are words that might sound similar to "celery" depending on pronunciation, they are not exact matches:
* Sellery is a possible misspelling, but it isn't a real word.
* Salary sounds similar, but the pronunciation is slightly different.
So, while there's no true homophone, there are words that sound close enough to be confused in certain contexts.