Other forms: rooting for; roots for; rooted for
When you root for someone, you wish for their success or cheer them on. You can root for your favorite baseball team from your living room, as you watch the game on TV.
You can wish your sister luck in the spelling bee and promise to root for her. You can also root for athletes you've never met, as you watch them compete in the Olympics. When you root for someone, you're on their side or in their corner. This phrase is an invention of American English that was originally used in the context of baseball, from a now obsolete meaning of the verb root, "work hard."