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
Cite this Entry
“Backside.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/backside. Accessed 22 Aug. 2026.
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