What is the true definition of a rebound relationship?

Hi i am currently separated 18 months now I filed for divorce this past april....While i think im over my STBX I recently met someone quite by accident ,I wasnt looking for anyone new.Although im enjoying the flattery flowersand the newness of the relationship. im also warey,scared & cautious & feeling very overwhelmed by his affection for me. He quite literally is sweeping me off my feet. I want to make sure in all fairness to him that this isnt a rebound thing. Hes my first date since my Ex any comments please would be appreciated..