(idiomatic) A person who collects rocks and minerals from the natural environment as a hobby.

An island of the Republic of Malta.

(slang) To jam at a concert, get down.

plural of rock group

plural of rock band

A group of musicians who regularly perform rock music together.

(slang, intransitive) To party to rock music, punk rock, grunge or heavy metal.

The off-white, crystal-like form of crack cocaine.

(informal) The species of diatom, Didymosphenia geminata, best known as widely invasive algae.

(US) A form of confectionery made by crystallizing sugar around a string.