any of the threadlike pigmented structures that grow from follicles beneath the skin of mammals and consist of layers of dead keratinized cells a growth of such structures, as on the human head or animal body, which helps prevent heat loss from the body any threadlike outgrowth from the epidermis, such as a root hair a fabric or material made from the hair of some animals - another word for hair's-breadth: to lose by a hair
- get in someone's hair ⇒
to annoy someone persistently - hair of the dog, hair of the dog that bit one ⇒
an alcoholic drink taken as an antidote to a hangover - keep your hair on! ⇒
keep calm - let one's hair down ⇒
to behave without reserve - not turn a hair ⇒
to show no surprise, anger, fear, etc - split hairs ⇒
to make petty and unnecessary distinctions
WordReference Random House Learner's Dictionary of American English © 2025
hair /hɛr/USA pronunciation
n.
hair•less, adj.
WordReference Random House Unabridged Dictionary of American English © 2025- Anatomy, Zoology any of many small, thin, tiny, threadlike pieces growing from the skin of mammals;
a pilus:[countable]She plucked a hair from her head. - Anatomy, Zoology[uncountable] a mass of such pieces, such as that covering the human head or forming the coat of most mammals.
- [ count;
usually singular;
a + ~] a very small amount or distance:The falling rock missed him by a hair.
- Idioms get in someone's hair, to annoy someone.
- let one's hair down, to to behave in a relaxed, informal manner.
- Idioms, Informal Terms make one's hair stand on end:
- to shock or frighten.
- Idioms split hairs, to make petty objections or distinctions:splitting hairs about the rules.
- Idioms tear one's hair (out), to behave frantically:tearing my hair out with worry.
hair•less, adj.
hair
(hâr),USA pronunciation n.
hair′like′, adj.
- Anatomy, Zoologyany of the numerous fine, usually cylindrical, keratinous filaments growing from the skin of humans and animals;
a pilus. - Anatomy, Zoologyan aggregate of such filaments, as that covering the human head or forming the coat of most mammals.
- Insectsa similar fine, filamentous outgrowth from the body of insects, spiders, etc.
- Botanya filamentous outgrowth of the epidermis.
- cloth made of hair from animals, as camel and alpaca.
- a very small amount, degree, measure, magnitude, etc.;
a fraction, as of time or space:He lost the race by a hair. - Idioms get in someone's hair, [Slang.]to annoy or bother someone:Their snobbishness gets in my hair.
- Idioms, Informal Terms 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.
- Informal Terms let one's hair down:
- to relax;
behave informally:He finally let his hair down and actually cracked a joke. - to speak candidly or frankly;
remove or reduce restraints:He let his hair down and told them about his anxieties.
- to relax;
- Idioms 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. - Idioms 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.
- Idioms 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.
- Idioms to a hair, perfect to the smallest detail;
exactly:The reproduction matched the original to a hair. - Idioms without turning a hair, without showing the least excitement or emotion. Also, not turn a hair.
- Old High German hāria (cognate with Middle English here, Old English hǣre, Old Norse hǣra)
- Old French
- Middle English heer, Old English hǣr (cognate with Dutch, German haar, Old Norse hār), with vowel perh. from Middle English haire hair shirt bef. 900
Collins Concise English Dictionary © HarperCollins Publishers::
'by a hair' also found in these entries (note: many are not synonyms or translations):