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

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

Examples of backside in a Sentence

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

Recent Examples on the Web

Use it to gently brush the microphone ports on each hearing aid, usually located on the backside of the device. —Christopher Null, Wired News, 22 June 2025

That particular highlight, a penalty box dance party that left half the Southampton team sprawling on their backsides before Giroud clipped the ball beyond Alex McCarthy, lights up his face. —Martin Rogers, New York Times, 16 June 2025

In addition to the views of the land, Jenner also shared a snap of her backside. —Dayna Haffenden, People.com, 12 June 2025

One viewer, however, chose to focus on the size of her backside — comparing it to previous online commentary instead of the performance itself. —Amber Corrine, VIBE.com, 4 June 2025

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