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hair

[hair]
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noun
  1. any of the numerous fine, usually cylindrical, keratinous filaments growing from the skin of humans and animals; a pilus.
  2. an aggregate of such filaments, as that covering the human head or forming the coat of most mammals.
  3. a similar fine, filamentous outgrowth from the body of insects, spiders, etc.
  4. Botany. a filamentous outgrowth of the epidermis.
  5. cloth made of hair from animals, as camel and alpaca.
  6. a very small amount, degree, measure, magnitude, etc.; a fraction, as of time or space: He lost the race by a hair.
Idioms
  1. get in someone's hair, Slang. to annoy or bother someone: Their snobbishness gets in my hair.
  2. hair of the dog, Informal. a drink of liquor, supposed to relieve a hangover: Even a hair of the dog didn't help his aching head.Also hair of the dog that bit one.
  3. let one's hair down, Informal.
    1. to relax; behave informally: He finally let his hair down and actually cracked a joke.
    2. to speak candidly or frankly; remove or reduce restraints: He let his hair down and told them about his anxieties.
  4. make one's hair stand on end, to strike or fill with horror; terrify: The tales of the jungle made our hair stand on end.
  5. split hairs, to make unnecessarily fine or petty distinctions: To argue about whether they arrived at two o'clock or at 2:01 is just splitting hairs.
  6. tear one's hair, to manifest extreme anxiety, grief, or anger: He's tearing his hair over the way he was treated by them.Also tear one's hair out.
  7. to a hair, perfect to the smallest detail; exactly: The reproduction matched the original to a hair.
  8. without turning a hair, without showing the least excitement or emotion.Also not turn a hair.

Origin of hair

before 900; Middle English heer, Old English hǣr (cognate with Dutch, German haar, Old Norse hār), with vowel perhaps from Middle English haire hair shirt < Old French < Old High German hāria (cognate with Middle English here, Old English hǣre, Old Norse hǣra)
Related formshair·like, adjectivede·hair, verb (used with object)
Can be confusedhair hare
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for split hairs

hair

noun
  1. any of the threadlike pigmented structures that grow from follicles beneath the skin of mammals and consist of layers of dead keratinized cells
  2. a growth of such structures, as on the human head or animal body, which helps prevent heat loss from the body
  3. botany any threadlike outgrowth from the epidermis, such as a root hair
    1. a fabric or material made from the hair of some animals
    2. (as modifier)a hair carpet; a hair shirt
  4. another word for hair's-breadth to lose by a hair
  5. get in someone's hair informal to annoy someone persistently
  6. hair of the dog or hair of the dog that bit one an alcoholic drink taken as an antidote to a hangover
  7. keep your hair on! British informal keep calm
  8. let one's hair down to behave without reserve
  9. not turn a hair to show no surprise, anger, fear, etc
  10. split hairs to make petty and unnecessary distinctions
Derived Formshairlike, adjective

Word Origin

Old English hær; related to Old Norse hār, Old High German hār hair, Norwegian herren stiff, hard, Lettish sari bristles, Latin crescere to grow
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for split hairs

hair

n.

Old English hær "hair, a hair," from Proto-Germanic *khæran (cf. Old Saxon, Old Norse, Old High German har, Old Frisian her, Dutch and German haar "hair"), perhaps from PIE *ghers- "to stand out, to bristle, rise to a point" (cf. Lithuanian serys "bristle;" see horror).

Spelling influenced by Old Norse har and Old English haire "haircloth," from Old French haire, from Frankish *harja or some other Germanic source (see above). To let one's hair down "become familiar" is first recorded 1850. Phrase hair of the dog that bit you (1540s), homeopathic remedy, is in Pliny.

Online Etymology Dictionary, © 2010 Douglas Harper

split hairs in Medicine

hair

(hâr)
n.
  1. Any of the cylindrical, keratinized, often pigmented filaments characteristically growing from the epidermis of a mammal.
  2. A growth of such filaments, as that forming the coat of an animal or covering the scalp of a human.
  3. One of the fine hairlike processes of a sensory cell.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

split hairs in Science

hair

[hâr]
  1. One of the fine strands that grow from the skin of mammals, usually providing insulation against the cold. Modified hairs sometimes serve as protective defenses, as in the quills of a porcupine or hedgehog, or as tactile organs, as in the whiskers (called vibrissae) of many nocturnal mammals. Hair filaments are a modification of the epidermis of the skin and are composed primarily of keratin. Hair also contains melanin, which determines hair color.
  2. A slender growth resembling a mammalian hair, found on insects and other animals.
  3. A fine, threadlike growth from the epidermis of plants. See more at trichome.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

split hairs in Culture

split hairs

To argue about an inconsequential and trivial aspect of an issue: “When you are accused of being forty-five minutes late for an appointment, you are splitting hairs to say that you were really only forty minutes late.”

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with split hairs

split hairs

Make trivial distinctions, quibble, as in Let's not split hairs about whose turn it is; I'll close up today and you do it tomorrow. This metaphoric idiom transfers dividing so fine an object as a single hair to other petty divisions. [Second half of 1600s]

hair

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.