An extra benefit is an additional advantage or privilege that someone receives beyond what is normally expected. It can come in the form of a PERK, FRILL, GRAVY, PLUS, or BONUS. A PERK is a small privilege or special benefit that is given to someone as a BONUS. A FRILL is an extra feature or decoration that is added to something to make it more attractive. GRAVY is an informal term for an extra benefit or advantage. PLUS is an additional benefit or advantage. Finally, a BONUS is an extra payment or reward given to someone for doing a good job.