brand-new
Completely new and unused, straight from the store.
Brand-new means completely new, never used before, and fresh from being made or bought. When you get a brand-new bicycle for your birthday, you're the first person to ever ride it. The tires have never touched the pavement, the paint is perfect, and it still has that factory smell. A brand-new book has crisp pages that no one has turned yet, and a brand-new video game comes sealed in its original packaging.
The term brand-new is stronger than just saying “new.” A shirt might be new to you because you just bought it at a thrift store, but it's not brand-new since someone else wore it first. Brand-new means absolutely fresh and unused, straight from the factory or store.
Today, when people want to emphasize just how new something is, they say it's brand-new or even brand-spanking-new. The moment you start using that brand-new thing, though, it stops being brand-new and becomes simply yours.