Belle

belle, feminine for beau (pronounced 'bo'), is an adjective that means beautiful

Some expressions with belle:
faire une (or la) belle = to play the last game in a best-of-three
se faire la belle = to run away
faire sa belle = to show off
l'avoir belle = to have an easy life
en faire voir de belles à quelqu'un = to give someone a hard time
la Belle au Bois dormant = Sleeping Beauty

Beau and belle are also used to refer to in-laws (which, I'm sure, some would find strange):
un beau-père / une belle-mère = a father/mother-in-law, but also stepfather/stepmother
un beau-frère / une belle-sœur = a brother/sister-in-law