masc. proper name, attested by 1218, probably via Anglo-French Jake, Jaikes, from Old French Jacques (which was a diminutive of Latin Jacobus; see Jacob), but in English the name always has been regarded as a familiar form of John, and some have argued that it is a native formation. In Middle English spelled Jakke, Jacke, etc., and pronounced as two syllables ("Jackie").

In England, Jack became a generic name applied familiarly or contemptuously to anybody (especially a young man of the lower classes) from late 14c. Later used especially of sailors (1650s; Jack-tar is from 1781); Jack-ashore (adj.) "drinking and in high spirits, recklessly spending" (1875) also is an image from sailors (1840 as a book title). In U.S., as a generic name addressed to an unknown stranger, attested from 1889. Every man Jack "everyone" is from 1812. Also see jack (n.).

Used in male personifications from 15c.; first record of jack-of-all-trades "person handy at any kind of work or business" is from 1610s; Jack Frost is from 1826; Jack-nasty "a sneak or sloven" is from 1833 (Jack-nasty-face, a sea-term for a common sailor, is from 1788). Jack Sprat for a small, light man is from 1560s (his opposite was Jack Weight). Jack-pudding "comical clown, buffoon" is from 1640s. Jack-Spaniard is from 1703 as a Spaniard, 1833 as "a hornet" in the West Indies. Other personifications listed in Farmer & Henley include jack-snip "a botching tailor," Jack-in-office "overbearing petty official" (1680s), Jack-on-both-sides "a neutral," Jack-out-of-doors "a vagrant" (1630s), jack-sauce "impudent fellow" (1590s).

The U.S. plant jack-in-the-pulpit (Indian turnip) is attested by 1833. Jack the Ripper was active in London 1888. The Scottish form is Jock (compare jockey (n.)). Alliterative coupling of Jack and Jill is from 15c. (Iakke and Gylle, Ienken and Iulyan). Jack Ketch for "hangman, executioner" (1670s) is said to be from the name of a public executioner in the time of James II (compare Derrick); it also was used as a verb meaning "to hang."

late 14c., jakke "a mechanical device," from the masc. name Jack. The proper name was used in Middle English for "any common fellow," and thereafter extended to various appliances which do the work of common servants (1570s). Also used generically of male animals (1620s, see jackass, jackdaw, etc.).

As a portable contrivance for raising weight by force from below, 1703. As the name of a device for pulling off boots from 1670s. The jack in a pack of playing cards (1670s) is in German Bauer "peasant." Slang meaning "money" is by 1890 (in earlier slang it meant "a small coin"). Jack-towel, one sewn together at the ends round a roller, is from 1795. The jack of Union Jack is a nautical term for "small flag at the bow of a ship" (1630s) and perhaps is from the word's secondary sense of "smaller than normal size."

Old English heah; see high (adj.).

1860, jack up "hoist, raise, lift with a jack," American English, from jack (n.) in the appliance sense. Figurative sense "increase (prices, etc.)" is 1904, American English. Related: Jacked; jacking. Jack off (v.) "masturbate" is attested from 1916, probably from jack (n.) in the old slang sense of "(erect) penis."

"the ordinary sound uttered by an ox or cow" [OED], 1540s, from low (v.); ultimately imitative.

"hill, small eminence," obsolete except in place names, from Old English hlaw "hill, mound," especially "barrow," a noun related to hleonian "to lean," from PIE root *klei- "to lean." Compare Latin clivus "hill," Greek klitys "side of a hill," from the same PIE root.

"not high, below the usual level," late 13c., earlier lah (late 12c.), "not rising much, being near the base or ground" (of objects or persons), also "lying on the ground or in a deep place" (late 13c.). This is not found in Old English, so the word is probably from Old Norse lagr "low, low-down, short; humble," or a similar Scandinavian source (compare Swedish låg, Danish lav), from Proto-Germanic *lega- "lying flat, low" (source also of Old Frisian lech, Middle Dutch lage, Dutch laag "low," dialectal German läge "flat"), from PIE root *legh- "to lie down, lay."

In reference to sounds, "not loud," also "having a deep pitch," from c. 1300. Meaning "humble in rank" is from c. 1200; "undignified, not high in character" is from 1550s; meaning "coarse, vulgar" is from 1759. Sense of "dejected, dispirited" is attested from 1737. Of prices, from c. 1400. In geographical usage, low refers to the part of a country near the sea-shore (c. 1300), as in Low Countries "Holland, Belgium, Luxembourg" (1540s). Low German languages (1845) are so called for being spoken in the lower elevations of old Germany.

Abject, low, and mean may have essentially the same meaning, but low is more often used with respect to nature, condition, or rank: mean, to character or conduct: abject, to spirit. [Century Dictionary, 1897]

Low blow in the figurative sense (1940s) is from pugilism. To lie low is from mid-13c. as "get down so as not to be seen," 1880 in the modern slang sense "keep quiet." Low Church in 18c. English history referred to Anglicans laying little stress on church authority (1702); in 19c. it meant evangelical Anglicans.

Old English hlowan "moo, make a noise like a cow," from Proto-Germanic imitative *khlo- (source also of Middle Dutch loeyen, Dutch loeien, Old Low Franconian luon, Old High German hluojen). This is perhaps identical with the imitative PIE root *kele- (2) "to shout."

"near the ground, not high," c. 1200, from low (adj.). Of voices or sounds, from c. 1300.

the low point of anything, the minimum, 1818, originally in card games; general sense by 1911.