Vroom is the sound of a powerful engine revving up or racing by. When you say vroom, you're imitating the deep, rumbling noise a car, motorcycle, or truck makes when it accelerates. Little kids pushing toy cars across the floor go vroom, vroom to bring their pretend races to life.

The word captures that satisfying growl of mechanical power. A sports car vrooming down the highway, a motorcycle vrooming past your house, or a race car vrooming around a track all make variations of this sound. The word itself seems to feel fast: those two o's in the middle stretch out like the sound of an engine holding a high speed.

You'll also see vroom used playfully to describe leaving quickly, like when someone says “Let's vroom out of here!” meaning “Let's go fast!” It's one of those wonderful words that sounds exactly like what it means, letting you hear the roar of engines even when you're just reading it on a page.