Mac Dictionary's definition:
1 the solid mineral material forming part of the surface of the earth and other similar planets, exposed on the surface or underlying the soil or oceans.
• a mass of such material projecting above the earth's surface or out of the sea : there are dangerous rocks around the island.
• Geology any natural material, hard or soft (e.g., clay), having a distinctive mineral composition.
• ( the Rock) Gibraltar.
• ( the Rock) informal name for Newfoundland 1 .
2 a large piece of such material that has become detached from a cliff or mountain; a boulder : the stream flowed through a jumble of rocks.
• a stone of any size, esp. one small enough to be picked up and used as a projectile.
• Brit. a kind of hard confectionery in the form of cylindrical peppermint-flavored sticks.
• informal a precious stone, esp. a diamond.
• informal a small piece of crack cocaine.
• ( rocks) vulgar slang testicles.
3 used in similes and metaphors to refer to someone or something that is extremely strong, reliable, or hard : imagining himself as the last rock of civilization being swept over by a wave of barbarism.
• (usu. rocks) (esp. with allusion to shipwrecks) a source of danger or destruction : the new system is heading for the rocks.
4 ( rocks) informal dated money.
PHRASES
between a rock and a hard place informal in a situation where one is faced with two equally difficult alternatives.
get one's rocks off vulgar slang have an orgasm. • obtain pleasure or satisfaction.
on the rocks informal 1 (of a relationship or enterprise) experiencing difficulties and likely to fail. 2 (of a drink) served undiluted and with ice cubes.
DERIVATIVES
rockless adjective
rocklike |-ˌlīk| adjective
ORIGIN Middle English : from Old French rocque, from medieval Latin rocca, of unknown ultimate origin.
rock 2
verb
1 [ trans. ] cause (someone or something) to move gently to and fro or from side to side : she rocked the baby in her arms.
• [ intrans. ] move in such a way : the vase rocked back and forth on its base | [as adj. ] ( rocking) the rocking movement of the boat.
• (with reference to a building or region) shake or cause to shake or vibrate, esp. because of an impact, earthquake, or explosion : [ trans. ] a terrorist blast rocked a Tube station | [ intrans. ] the building began to rock on its foundations.
• cause great shock or distress to (someone or something), esp. so as to weaken or destabilize them or it : diplomatic upheavals that rocked the British Empire.
2 [ intrans. ] informal dance to or play rock music.
• figurative (of a place) have an atmosphere of excitement or much social activity : the new town really rocks | [as adj. ] ( rocking) a rocking resort.
noun
1 rock music : [as adj. ] a rock star.
• rock and roll.
2 [in sing. ] a gentle movement to and fro or from side to side : she placed the baby in the cradle and gave it a rock.
PHRASES
rock the boat see boat .
PHRASAL VERBS
rock out informal perform rock music loudly and vigorously. • enjoy oneself in an enthusiastic and uninhibited way, esp. by dancing to rock music.
ORIGIN late Old English roccian, probably from a Germanic base meaning ‘remove, move’ ; related to Dutch rukken ‘jerk, tug’ and German rücken ‘move.’ The noun dates from the early 19th cent.