[ nit ]
/ nɪt /
Save This Word!


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



Apostrophes can be tricky; prove you know the difference between it’s and its in this crafty quiz!
Question 1 of 12
On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

Origin of nit

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”

Definition for nit (2 of 3)

[ nit ]
/ nɪt /

noun Physics.

a unit of luminous intensity equal to one candela per square meter. Abbreviation: nt

Origin of nit

1950–55; extracted from Latin nitor brightness; see nitid, -or1

Definition for nit (3 of 3)

[ nit ]
/ nɪt /

noun Chiefly British.

a nitwit.

Origin of nit

By shortening
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021


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.

Where does nit come from?

The first records of nit come from before the 900s. It comes from the Old English hnitu, and many languages have similar words that all mean the same thing.

Lice have plagued humans for ages, and to get rid of every last louse (the singular form of lice) you have to pick out every last nit. The image of picking nits out of someone’s hair gives us the word nitpick (or nitpick), meaning “to point out the very minor flaws or mistakes in something.” People sometimes use the word nit (in humorous reference to the word nitpick) as a noun meaning “a minor issue, flaw, or complaint,” as in I have just a few nits to pick with your paper.

Nit can be synonymous with nitwit (“a stupid or foolish person”), but the origin of nit in nitwit is uncertain. It may be a reference to louse eggs (which is a pretty sick insult), but it could also derive from an informal German word for not. The origin of nitty in nitty-gritty is also uncertain.

Nit is also used in a few contexts that are completely unrelated to louse eggs. In Australian slang, to keep nit is to keep watch. In physics, it’s a unit that measures luminance. In information science, a nit is a unit of information equal to 1.44 bits, also called a nepit. The word knit is completely unrelated.

Did you know ... ?

What are some synonyms for nit?

What are some words that share a root or word element with nit

What are some words that often get used in discussing nit?


What are some words nit may be commonly confused with?



How is nit used in real life?

Nit is most commonly used in discussions of lice.



Try using nit!

Is nit used correctly in the following sentence? 

I’d rather be called a nitpicker than pick actual nits.

British Dictionary definitions for nit (1 of 5)

/ (nɪt) /


the egg of a louse, especially when adhering to human hair
the larva of a louse or similar insect
Old English hnitu; related to Dutch neet, Old High German hniz

British Dictionary definitions for nit (2 of 5)

/ (nɪt) /


a unit of luminance equal to 1 candela per square metre
C20: from Latin nitor brightness

British Dictionary definitions for nit (3 of 5)

/ (nɪt) /


informal, mainly British short for nitwit

British Dictionary definitions for nit (4 of 5)

/ (nɪt) /


a unit of information equal to 1.44 bitsAlso called: nepit
C20: from N (apierian dig) it

British Dictionary definitions for nit (5 of 5)

/ (nɪt) /


keep nit Australian informal to keep watch, esp during illegal activity
C19: from nix 1
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

Medical definitions for nit

[ nĭt ]


The egg or young of a parasitic insect, such as a louse.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Get Online Help For Kids!