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

The signature high-waist style now comes in everything from ankle-length straight legs and slim, tapered fits to bootcuts and capris, retaining the cheeky backside pocket detailing. — Kristina Rutkowski, Vogue, 29 Oct. 2026

Amid dealing with a custody battle that cut time with her two small boys down to alternating weeks, says Butler, her friends hauled her camping on the backside of Pikes Peak in central Colorado and introduced her to target shooting during the trip. — Heide Brandes, Condé Nast Traveler, 28 Oct. 2026

The woolly fur on his backside is tightly clipped; at his head, the fur is combed into a topknot secured with a little pink bow. — Literary Hub, 28 Oct. 2026

Another nice touch is the super-adjustable seat post, which can place your backside anywhere from 30-42 inches (76-107 cm) from the ground, comfortably welcoming riders from 4 ft 10 in to 6 ft 2 in (147 to 188 cm). — Loz Blain october 26, New Atlas, 27 Oct. 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