Etymology
Advertisement
shelf (n.2)

"sandbank, underwater ridge," 1540s, a word of obscure origin; evidently identical to Middle English shelp "sandbar in a river" (early 15c.), but the sound shift is unexpected. Shelp might be from Old English scylp "crag" or Middle Dutch schelp-. Also sometimes regarded as a particular use of shelf (n.1) or from the verbs shelve. Related: Shelfy "abounding in sandbanks."

Related entries & more 
Advertisement
shelf (n.1)

late 14c., "thin slab or plank fixed horizontally to a wall or frame and used for supporting small objects; a transverse board in a case or cabinet," perhaps from Middle Low German schelf "shelf, set of shelves," or perhaps from Old English cognate scylfe, which could have meant "shelf, ledge, floor, deck of a ship" (the sense is uncertain), and scylf "peak, pinnacle."

These all are from Proto-Germanic *skelf- "split," possibly from the notion of a split piece of wood (compare Old Norse skjölf "bench"), from an extended form of the PIE root *skel- (1) "to cut," and thus distantly related to shell, etc.

From mid-15c. as "grassy bank." The meaning "ledge of rock" (as in later continental shelf) is from 1809, perhaps from or influenced by shelf (n.2).

By 1920s in reference to the display of goods in a shop, hence shelf life "time goods may be kept or stored unsold before they begin to spoil" (1927). The figurative phrase on the shelf "out of the way, inactive" is attested from 1570s (also used 19c. of unmarried women with no prospects). Off the shelf "ready-made, from a supply of ready-made goods" is from 1936. Related: Shelves.

Related entries & more 
off (prep., adv.)

by c. 1200 as an emphatic form of Old English of (see of), employed in the adverbial use of that word. The prepositional meaning "away from" and the adjectival sense of "farther" were not firmly fixed in this variant until 17c., but once they were they left the original of with the transferred and weakened senses of the word. Meaning "not working" is from 1861.

Off the cuff "extemporaneously, without preparation" (1938) is from the notion of speaking from notes written in haste on one's shirt cuffs. In reference to clothing, off the rack (adj.) "not tailored, not made to individual requirements, ready-made" is by 1963, on the notion of buying it from the rack of a clothing store; off the record "not to be publicly disclosed" is from 1933; off the wall "crazy" is 1968, probably from the notion of a lunatic "bouncing off the walls" or else in reference to carom shots in squash, handball, etc.

Related entries & more 
off (v.)

"to kill," 1930, from off (adv.). Earlier verbal senses were "to defer" (1640s), "to move off" (1882). Related: Offed.

Related entries & more 
far-off (adj.)

also faroff, "distant, remote," 1590s, from adverbial phrase, from far (adv.) + off (adv.).

Related entries & more 
Advertisement
off-camera (adv.)

"outside the range of a film or television camera," 1944, from off (prep.) + camera.

Related entries & more 
off-stage (adj.)

also offstage, "occurring away from a (theatrical) stage," 1915, from off (prep.) + stage (n.).

Related entries & more 
twist-off (adj.)

of bottle or jar caps, 1959, from the verbal phrase; see twist (v.) + off (adv.).

Related entries & more 
off-target (adj.)

"missing what was aimed at," 1947 (in reference to missiles), from off (prep.) + target (n.).

Related entries & more