also rock 'n' roll, 1952 in reference to a specific style of popular music, from rock (v.2) + roll (v.). The verbal phrase had been an African-American vernacular euphemism for "sexual intercourse," used in popular dance music lyrics and song titles at least since the 1930s. Shortened form rock by 1956.

The original rock and roll of the early 1950s is sometimes difficult to parse as belonging to the same genre as what was later called by the term, and it is likely that the true genre of rock and roll did not last long, but that the denomination continued to be applied by record companies to other kinds of music that had been influenced by it or were felt to be related. The term was popularized ca. 1954 by disk jockey Alan "Moondog" Freed (1921 - 1965) as a synonym for what had previously been called R&B (see R).

The stock answer to whether Rock music has gone as far as it can was "no." People just differed on which way it was going. [Kiki Morris, The Herald Statesman, Yonkers, NY, Dec 9, 1970.]

Folk rock is by 1964, pop rock by 1965, psychedelic rock by 1966, punk rock by 1971, southern rock by 1971, hard rock and soft rock by 1967, Christian rock by 1972, glam rock by 1972, gothic rock by 1977, alternative rock by 1979, classic rock meaning "rock performed by classical orchestras" is by 1978, meaning "rock from 1960s and 1970s" is by 1982, J-rock "Japanese rock" is by 2003. See also rockabilly.

"moving back and forth or to and fro," late 14c., rokking, present-participle adjective from rock (v.1). Of music, from 1949 (see rock (v.2)). Rocking-horse "wooden horse mounted on rockers for children" is recorded from 1724; rocking-chair "chair mounted on rockers" is from 1766.

also bed-rock, in geology, "solid rock lying under soil or gravel," 1850, from bed (n.) + rock (n.). Figurative use by 1869; as an adjective by 1881.

type of gait of a horse, between a trot and a gallop or canter, 1580s, from rack (v.) "move with a fast, lively gait" (1520s, implied in racking), which is of unknown origin; perhaps from French racquassure "racking of a horse in his pace," itself of unknown origin. Or perhaps a variant of rock (v.1).

type of popular music blending elements of rock 'n' roll and hillbilly music, 1956, from rock (n.2) in the music sense + second element abstracted from hillbilly music. One of the first uses is in a Billboard magazine item about Johnny Burnette's "Lonesome Train."

phrase in nursery rhyme sleeping-songs, by 1805; see rock (v.1). Compare lullaby.

"lowest possible," 1884, from the noun phrase meaning "bedrock" (1815), also figurative, from rock (n.1) + bottom (n.).

"hard confection made of pure sugar in crystals of considerable size," 1723, from rock (n.1) + candy (n.).

1852, "a rocking chair," American English, agent noun from rock (v.1). Middle English had rokker, "nurse charged with rocking a cradle" (early 14c.). In sense of "one of the curved pieces of wood that makes a chair or cradle rock" it dates from 1787. Meaning "one who enjoys rock music" (opposed to mod (n.1)) is recorded from 1963, from rock (v.2).

Slang off (one's) rocker "crazy" is attested by 1897 according to OED; a widely reprinted 1903 newspaper column in U.S. identified it as British slang; the image is perhaps mechanical. To get (off) one's rocker seems to have been used earlier in U.S. baseball slang for "get busy, get active in a game" (1895) and does suggest the rocking-chair.

"vertical expanse of natural rock," 1847, from rock (n.1) + face (n.).