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

When strength training later in life, more attention must be paid to building strength around the joints, Herbert says, and strengthening the posterior, or back, chain of the body.

From Los Angeles Times ● Oct. 27, 2025

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

Dr. Keith Meister performed the surgery in Arlington, Texas, to repair what Hollander described as a small tear in the posterior of Brash’s ulnar collateral ligament.

From Seattle Times ● May 10, 2024

Panel recommendations include transvaginal ultrasound of the posterior compartment, observation of the relative positioning of the uterus and ovaries, and the uterine sliding sign maneuver to improve the detection of endometriosis.

From Science Daily ● Apr. 9, 2024

He plumped his large posterior onto the lavatory pan.

From "1984" by George Orwell

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

So I, when I am ready to go beside myself, stick my head into a story-book, as the ostrich with her bush; let fate and fortune meantime belabour my posteriors at their will.

From The Works of Robert Louis Stevenson - Swanston Edition Vol. 23 (of 25) by Robert Louis Stevenson

Related Words

• backside
• derriere
• fanny
• rear end
• rump