backside

noun

back·​side ˈbak-ˌsīd 

1

informal

a

: the part of the body that a person sits on : buttocks

I slid down on my backside, heaving or rowing myself with my arms and using my good leg for steering …

—Oliver Sacks

b

: the part of the body of a four-legged animal corresponding to the buttocks : rump sense 1a

… admits she hit the dog's backside but denies hitting it on the head.

—Ann Krueger

2

or back side : the side or surface opposite the front or face of something : the farthest or reverse side : back

A tight, rocky couloir drops down the backside of the peak …

—Mike Beaudry

The guy with the clipboard pulled me over, pointed to an innocuous little knob on the back side of the engine and said it's part of the computer and needs to be replaced.

—Tom and Ray Magliozzi

3

or back side

a

: the side opposite the homestretch on a racecourse : backstretch

When challenged on the backside the final time around, Tudor Palm would have no part of it, and burst to the lead again.

—Jackie Burke

b

: the part of a playing field or court (as in football or basketball) that is away from where the main action or play is occurring

—often used before another noun

a backside tackle

c

: the final 9 holes of an 18-hole golf course

The duo had a little trouble on the backside, though, as they bogeyed the par-3 11th hole.

—Brian Girasoli

Synonyms of backside

• cheeks
• bum
• seat
• tail
• rump
• bottom
• rear

Examples of backside in a Sentence

our backsides were sore after sitting on those hard benches for so long

Recent Examples on the Web

Neymar, Brazil’s last mononym star, is now on the backside of his career. — Andrew Greif, NBC news, 30 June 2026

Seven years later, he has been injured, apathetic, entitled, disconnected and generally nothing but a pain in the backside for a reenergized franchise that deserved so much better. — Assistant Sports Editor, Los Angeles Times, 29 June 2026

Its compressive fabric keeps the bust supported, and the high cut and moderate backside coverage still lend a youthful feel, without baring it all. — Christina Shepherd McGuire, PEOPLE, 28 June 2026

Another big technology built into the 18A is called PowerVia, which is described as a backside power delivery system. — John Werner, Forbes.com, 27 June 2026

Word History

First Known Use

14th century, in the meaning defined at sense 2

Rhymes for backside

• abide
• allied
• applied
• aside
• astride
• azide
• bankside
• bastide
• bayside
• bedside
• belied
• beside

Kids Definition

backside

noun

back·​side ˈbak-ˈsīd 

informal

: buttock sense 2a

Medical Definition

backside

noun

back·​side -ˌsīd 

: buttocks

—often used in plural