posterior

American  

[po-steer-ee-er, poh-] / pɒˈstɪər i ər, poʊ- /

adjective

1. situated behind or at the rear of; hinder (opposed to anterior).

2. coming after in order, as in a series.

3. coming after in time; later; subsequent (sometimes followed byto ).

4. Anatomy, Zoology.

   1. (in quadrupeds) pertaining to or toward the rear or caudal end of the body.

   2. (in humans and other primates) pertaining to or toward the back plane of the body, equivalent to the dorsal surface of quadrupeds.

5. Botany. toward the back and near the main axis, as the upper lip of a flower.

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noun

• posteriors
  plural

1. the hinder parts or rump of the body; buttocks.

posterior British  

/ pɒˈstɪərɪə /

adjective

1. situated at the back of or behind something

2. coming after or following another in a series

3. coming after in time

4. zoology (of animals) of or near the hind end

5. botany (of a flower) situated nearest to the main stem

6. anatomy dorsal or towards the spine

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noun

1. the buttocks; rump

2. statistics a posterior probability

Synonym Usage

See back ¹.

Other Word Forms

Derived Forms

• posteriorly
  adverb

Inflected Forms

Nouns

• posteriors
  plural

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Etymology

Origin of posterior

1525–35; < Latin, comparative of posterus coming after, derivative of post after

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Explanation

Use the adjective posterior to describe something that's in the back. It’s often used in anatomy — a posterior cerebral artery supplies blood to the back of the brain, and the tail is on the posterior of a fish. The prefix post means “after,” and things that are posterior come after the things in the front. The opposite of posterior is anterior, which refers to the front, usually of body parts. You can also use the word posterior to jokingly refer to the part of your body that you sit on — your backside. Posterior is also a formal way to say later in time.

Example Sentences

See Examples For:

posterior posteriors

A friend in her 80s slipped on the stairs to her flooded basement and fell, breaking two posterior ribs and injuring her shoulder.

From MarketWatch ● Oct. 5, 2026

The change began in the posterior cortex and then moved forward, pointing to a large-scale process that may prepare the brain metabolically for REM sleep.

From Science Daily ● Sep. 26, 2026

To offset that, he pays extra attention to strengthening the posterior, or back, chain of their bodies.

From Los Angeles Times ● Jan. 1, 2026

Research has shown that the premotor and posterior parietal cortices, along with the temporoparietal junction, are active in the brain when we are locating or thinking about ourselves.

From Salon ● May 26, 2025

I should record them for posterity—a word I only recently learned means the people who come after you in history, not your rear end, which is your posterior.

From "A Mango-Shaped Space" by Wendy Mass

Today, those same simulated posteriors are essential to making sure new sensors are in good working order.

From The Wall Street Journal ● Feb. 20, 2026

Those lucky enough to have got their posteriors on the leather seats of ministerial cars all know the situation is bad.

From BBC ● Sep. 2, 2023

This from someone who refers to his players’ posteriors as “tails” — as in, “They practiced their tails off this week.”

From Los Angeles Times ● Sep. 15, 2019

“They kicked our ass,” Texas Coach Tom Herman, then the offensive coordinator at Ohio State, recalled this past summer, but they just did not kick it in the way other posteriors have gotten kicked lately.

From Washington Post ● Nov. 12, 2017

He carries a little switch, rather, it would appear, for form's sake; for he seldom does more with it than tickle the gravely striding posteriors of the quaint little people.

From Prose Fancies by Richard Le Gallienne

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Related Words

• backside
• derriere
• fanny
• rear end
• rump

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