early 14c., "feeling of disgust;" late 14c., "emotion of horror or dread," also "thing which excites horror," from Old French horror (12c., Modern French horreur) and directly from Latin horror "dread, veneration, religious awe," a figurative use, literally "a shaking, trembling (as with cold or fear), shudder, chill," from horrere "to bristle with fear, shudder," from PIE root *ghers- "to bristle" (source also of Sanskrit harsate "bristles," Avestan zarshayamna- "ruffling one's feathers," Latin eris (genitive) "hedgehog," Welsh garw "rough").

Also formerly in English "a shivering," especially as a symptom of disease or in reaction to a sour or bitter taste (1530s); "erection of the hairs on the skin" (1650s); "a ruffling as of water surface" (1630s). As a genre in film, 1934. Chamber of horrors originally (1849) was a gallery of notorious criminals in Madame Tussaud's wax exhibition. Other noun forms are horribility (14c., now rare or disused), horribleness (late 14c.), horridity (1620s), horridness (1610s).

also crosshair, cross-hairs, "very fine line (originally spider's silk) stretched across the focal plane of a telescope or microscope, forming a cross with another," 1755 of a telescope, 1780 in gunnery, from cross- + hair (n.). Also often in early 19c. spider-line, spider's-line (1819).

1712, from hair + ball (n.1).

also hairsbreadth, hairs-breadth, hair's breadth, from late 15c. as a measure of minute exactness. It is said to once have been a formal unit of measure equal to one-forty-eighth of an inch. From hair + breadth.

also hair-brush, 1590s, from hair + brush (n.1).

cloth made from the shorter hairs of animals, early 15c., from hair + cloth.

also hair-cut, 1887, "act of cutting the hair," from hair (n.) + cut (n.). As "style of wearing the hair," by 1890.

The Romans began to cut the hair about A.U.C. 454, when Ticinius Maenas introduced Barbers from Sicily. Then they began to cut, curl, and perfume it. The glass was consulted as now upon rising from the barber's chair. [Rev. Thomas Dudley Fosbroke, "Encyclopædia of Antiquities," London, 1825]

Related: Haircutter; haircutting.

also hair-do, 1932, from hair + do (v.). Phrase do (one's) hair attested from 1875.

also hair-dresser, 1770, from hair + dresser. Related: Hairdressing (1771).

1550s, from hair + -less. Related: Hairlessness.