A perk is an extra benefit or advantage that comes along with something, beyond what you'd normally expect. When a job offers free lunch to employees, that's a perk. When a hotel lets guests use the swimming pool and game room, those are perks of staying there. The word comes from “perquisite,” but almost everyone just says perk.

Perks make situations more appealing or enjoyable. A student might consider the perks of joining the science club: maybe they get first access to the new microscopes or special field trip opportunities. Your parents might choose a particular credit card because of its perks, like earning points toward free flights or getting discounts at certain stores.

Sometimes “perk” works as a verb too. When you perk up, you become more alert and energetic, like a plant perking up after you water it. Coffee is famous for perking people up in the morning. You might notice your dog's ears perk up when they hear you opening a treat bag.

While perks are nice additions, they're extras, not the main thing. A job's main purpose is the work and salary, but good perks can make it more attractive. A book's main value is the story, but beautiful illustrations can be a delightful perk.