Evan Rachel Wood Elbowed In the Face -- LOSES A TOOTH

Evan Rachel Wood took a serious shot to the face last night in Europe -- in the form of a wild elbow that actually KNOCKED OUT one of her teeth ... TMZ has learned.

Sources close to Wood tell us, the actress was hanging out with some friends in Paris -- and decided to hit up some local spot with music and dancing.

We're told one of the dancers at the establishment got a little loose with the elbows -- and accidentally connected with Wood's mouth, knocking out a tooth ... and giving her one fat lip.

Wood -- who's traveling the world to promote her new movie "Ides of March" and her HBO miniseries "Mildred Pierce" -- will continue on the tour ... but sources tell us she's already meeting with a dentist to get a replacement tooth.

FYI -- it's Evan Rachel's birthday today. Happy birthday!!!