hair

American  

[hair] / hɛər /

noun

• hairs
  plural

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.

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idioms

1. tear one's hair, to manifest extreme anxiety, grief, or anger: Also tear one's hair out.

   He's tearing his hair over the way he was treated by them.

2. 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.

3. 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.

4. without turning a hair, without showing the least excitement or emotion. Also not turn a hair.

5. to a hair, perfect to the smallest detail; exactly.

   The reproduction matched the original to a hair.

6. hair of the dog, a drink of liquor, supposed to relieve a hangover: Also hair of the dog that bit one.

   Even a hair of the dog didn't help his aching head.

7. let one's hair down,

   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.

8. get in someone's hair, to annoy or bother someone.

   Their snobbishness gets in my hair.

hair British  

/ hɛə /

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

4. 1. a fabric or material made from the hair of some animals

   2. ( as modifier )

      a hair carpet

      a hair shirt

5. another word for hair's-breadth

   to lose by a hair

6. informal to annoy someone persistently

7. an alcoholic drink taken as an antidote to a hangover

8. informal keep calm

9. to behave without reserve

10. to show no surprise, anger, fear, etc

11. to make petty and unnecessary distinctions

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hair Scientific  

/ 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.

4. See more at trichome

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hair More Idioms  

More idioms and phrases containing hair

• bad hair day
• by a hair
• by the short hairs
• fair-haired boy
• get gray hair from
• hang by a thread (hair)
• hide or hair
• in someone's hair
• let one's hair down
• make one's hair stand on end
• put lead in one's pencil (hair on one's chest)
• split hairs
• tear one's hair
• turn a hair

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Other Word Forms

Derived Forms

• dehair
  verb (used with object)
• hairlike
  adjective

Inflected Forms

Nouns

• hairs
  plural

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Etymology

Origin of hair

First recorded 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,” from Old French, from Old High German hāria (cognate with Middle English here, Old English hǣre, Old Norse hǣra )

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Explanation

Hair is the strands of fiber that grow from a person's skin, especially on the scalp. Most mammals, from dogs to bears to mice, also have hair. Your hair might be straight or curly, brown or gray or dark red. Even people with no hair on their heads have body hair, short, fine hairs that grow on arms and legs. Cats have coats that vary too, ranging from hairless to long, silky hair. Even some plants can be described as having hair. Colloquially, people "split hairs," or argue about unimportant things, or tell a "hair-raising" tale, or a spooky story that gives you chills.

Example Sentences

See Examples For:

hair hairs

In the 1990s, Frieda stepped back from cutting hair and concentrated on developing his own brand of hair products, including Frizz-Ease hair serum which he created in 1988.

From BBC ● Nov. 4, 2026

Mr. Homme trills cryptic lines like “Keep your hair down, don’t turn around” with a fey tone reminiscent of Jeff Buckley or Thom Yorke.

From The Wall Street Journal ● Nov. 3, 2026

Their faces are vivid, and haunting, whether bearing signs of greying hair and wrinkles, or the long eyelashes and chubby cheeks of a child.

From Barron's ● Nov. 3, 2026

You see everybody on camera all the time, and so it liberated every woman in the room to “OK, good, she knows her hair is going crazy right now.”

From Los Angeles Times ● Nov. 2, 2026

When Dad first walked into the school and saw me, he wasn’t shocked by what I’d done to my hair.

From "Split the Sky" by Marie Arnold

The $50,000 was a gift, not a loan and that, to split hairs, is being used as the bargaining chip.

From MarketWatch ● Oct. 9, 2026

It said it was distinctive with a velvety covering of ginger-yellow hairs across its body and no black hairs.

From BBC ● Sep. 27, 2026

Cilia, tiny hairs that clear mucus out of the lungs, resume working within weeks, prompting coughing that clears the lungs.

From The Wall Street Journal ● Jul. 23, 2026

The new Fed chairman, Kevin Warsh, has said he isn’t interested in splitting hairs, adding that he prefers to focus on how the inflation rate looks “to the left of the decimal point.”

From The Wall Street Journal ● Jul. 19, 2026

He zeroed in on my scalp and pinched a group of hairs at the root, sliding mysterious debris to the end and setting off a ripple of chills from my shoulders to my face.

From "The Line Tender" by Kate Allen

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