noun
General term for a rock or boulder of any size, from a stone you can hold to a massive cliff face.
海岸に大きな岩がごろごろしている。
There are big rocks scattered along the shore.
彼は岩を投げて川に落とし
He threw a rock into the river.
noun
crag; rugged rock
Emphasizes a steep, rugged, or imposing rock face; often used in literary or descriptive contexts. 巌 is especially associated with this sense.
断崖の岩に波が打ち寄せる。
Waves crash against the crag of the cliff.