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

Etymology

Origin of posterior

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

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

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

From Los Angeles Times ● Jan. 1, 2026

As a parent, the first time I saw one of my sons talk out of their posterior on a subject they knew nothing about, I laughed.

From Salon ● Oct. 24, 2025

Dyeing poison frogs, Dendrobates tinctorius, have been shown to tap their posterior toes in response to a range of prey sizes, from small fruit flies to large crickets.

From Science Daily ● May 28, 2024

The US Ski & Snowboard Team said Shiffrin would continue to be assessed but her anterior and posterior cruciate ligaments "seem intact".

From BBC ● Jan. 26, 2024

At one end sat Chiron the centaur, his equine posterior collapsed into his magic wheelchair so he looked like a regular human.

From "Blood of Olympus" by Rick Riordan

It's not just about red boxes and posteriors on the seats of government cars.

From BBC ● Jun. 27, 2026

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

The legion resulting posteriors may protrude into the seawater through natural holes in the sponge and amble along its surface.

From Scientific American ● Aug. 8, 2021

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

Yes, dear Gelid, so sure as you have been landed down on your posteriors now—ah—you shall be handed down to your posterity hereafter, by that pestilent little scamp Cringle.

From Tom Cringle's Log by Michael Scott

Related Words

• backside
• derriere
• fanny
• rear end
• rump