Rock

Concise Oxford English Dictionary © 2008 Oxford University Press:
rock1

▶noun

• 1 the hard mineral material of the earth's crust, exposed on the surface or underlying the soil.

  ■ a mass of this projecting out of the ground or water.

  ■ (the Rock) Gibraltar.

  ■ a boulder.

  ■ N. Amer. a stone of any size.

• 2 Geology any natural material with a distinctive mineral composition.

• 3 Brit. a kind of hard confectionery in the form of cylindrical peppermint-flavoured sticks.

• 4 informal a diamond or other precious stone.

• 5 informal a small piece of crack cocaine.

• 6 (rocks) vulgar slang a man's testicles.

– phrases
between a rock and a hard place informal faced with two equally difficult alternatives.
get one's rocks off vulgar slang have an orgasm.
on the rocks informal

• 1 experiencing difficulties and likely to fail.

• 2 (of a drink) served undiluted and with ice cubes.

– derivatives
rockless adjective,
rock-like adjective.

– origin ME: from OFr. rocque, from med. L. rocca.

Concise Oxford English Dictionary © 2008 Oxford University Press:
rock2

▶verb

• 1 move gently to and fro or from side to side.

  ■ shake, especially because of an earthquake or explosion.

• 2 cause great shock or distress to.

• 3 informal dance to or play rock music.

• 4 informal (of a place) be exciting or full of social activity.

• 5 (rock up) arrive; turn up.

• 6 informal wear (a garment) or affect (an attitude or style), especially in a confident or flamboyant way: Iverson was rocking a stars and stripes skullcap.

▶noun

• 1 (also rock music) a form of popular music derived from rock and roll and pop music but characterized by a more serious approach.

  ■ rock and roll.

• 2 a rocking movement.

– origin OE roccian, prob. from a Gmc base meaning ‘remove, move’.