A rocket-propelled vehicle constrained to run on a rail, used for experimental purposes.

Fine-grained, silt-sized particles of rock generated by mechanical grinding of bedrock by glacial erosion or artificially.

Alternative spelling of rock and roll

(geology) An igneous rock that crystallized at considerable depth in the crust; plutonic rock.

A rock from the surface of the moon, but especially any geological specimen brought back by the Apollo program

(space science) A suborbital rocket used to launch upper atmosphere, exoatmospheric, and microgravity sondes or probes.

Alternative form of rocket-propelled grenade

(Scientology) An erratic slashing motion of an E-meter's needle, supposed to indicate evil intentions in the subject.

plural of rock slam

A rhythmically complex, often guitar-based style of experimental rock music that emerged in the late 1990s.