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Synonyms

nit

1 American  
[nit] / nɪt /

noun

  1. the egg of a parasitic insect, especially of a louse, often attached to a hair or a fiber of clothing.

  2. the young of such an insect.


nit 2 American  
[nit] / nɪt /

noun

Chiefly British.
  1. a nitwit.


nit 3 American  
[nit] / nɪt /

noun

Physics.
  1. a unit of luminous intensity equal to one candela per square meter. nt


nit 1 British  
/ nɪt /

noun

  1. the egg of a louse, especially when adhering to human hair

  2. the larva of a louse or similar insect

"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

nit 2 British  
/ nɪt /

noun

  1. a unit of luminance equal to 1 candela per square metre

"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

nit 3 British  
/ nɪt /

noun

  1. informal short for nitwit

"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

nit 4 British  
/ nɪt /

noun

  1. Also called: nepit.  a unit of information equal to 1.44 bits

"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

nit 5 British  
/ nɪt /

noun

  1. informal to keep watch, esp during illegal activity

"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

Usage

What does nit mean? Nits are the eggs or young of small parasitic insects, most commonly lice. They are especially called this when they are attached to hair. Nit is the basis of the word nitpick. Nit is also used as an insult referring to a stupid person, though in this case it’s a shortening of the word nitwit, which may or may not be related. Example: Your scalp won’t be free of lice until you remove all the nits.

Etymology

Origin of nit1

First recorded before 900; Middle English nite, nete, nette, Old English hnitu, cognate with Dutch neet, German Niss, Old Icelandic gnit, Norwegian gnett; akin to Welsh nedd, Polish gnida, Greek konís (stem konid- ), from Proto-Indo-European root knid- “egg of a louse”

Origin of nit2

First recorded in 1590–1600; perhaps from nit 1 ( def. ); perhaps from nit(wit) ( def. )

Origin of nit3

First recorded in 1950–55; from French, extracted from Latin nitor “brightness, splendor”; nitid, -or 1

Explanation

A nit is a louse egg. If your scalp is extra itchy, get someone (maybe even a "nitpicker" to check you for nits. There's no getting around the fact that nits are pretty gross — they're basically baby lice. Nits can be tricky to spot on an infested person's scalp, because they're smaller than a grain of rice and a very pale color. Colloquially, to "nit pick" is to find and criticize someone's faults, no matter how tiny they might be. Another, less disgusting kind of nit is a scientific term for an amount of light emitted.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

But the Surge’s bylaws are clear that no nit be left unpicked, and so we have to quibble with his framing.

From Slate • Jan. 17, 2026

But in a standout performance, that was perhaps the only nit one could pick.

From Los Angeles Times • Oct. 9, 2022

Thairo Estrada nit a double that scored Davis with one out and preceded Bart’s two-run double.

From Seattle Times • Aug. 15, 2022

It features a bright 700 nit 5.5-inch built-in screen that eliminates the need for a phone.

From The Verge • May 10, 2022

No: I could not but smile thro' my chafe: For the fellow lay safe As his mates do, the midge and the nit, —Thro' minuteness, to wit.

From Browning's Shorter Poems by Baker, Franklin T. (Franklin Thomas)