What does backside mean?
Backside is an informal noun most commonly used to denote the buttocks — the fleshy part of the body on which a person sits. It appears frequently in everyday speech and light humour, often in phrases about falling down, being kicked, or being told to get moving. In British English, backside has a second, older sense: the rear portion of a building, plot of land, or object, as in 'the backside of the house'. This spatial use is less common today and can sound dated or regional. The word carries a casual, sometimes mildly comic connotation, making it well suited to conversation but out of place in formal writing, where terms like 'buttocks' or 'posterior' are preferred. Its transparent formation from 'back' plus 'side' makes its meaning immediately clear even to new learners of English.
The buttocks; the part of the body on which a person sits.
"He tumbled off the ladder and landed flat on his backside."
Informal; often used humorously.
(Chiefly British) The rear or back part of a building, piece of land, or object.
"The kitchen garden lay at the backside of the cottage."
Largely British and somewhat dated.
The plural is regular. It is most often used when speaking of several people's buttocks, usually in informal or humorous contexts.
"The coach threatened to kick the whole team's backsides into gear."
In British English, 'backside' can describe the rear of a house — so you can literally live in the backside of a building.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of backside
Backside is formed transparently within English from the native words 'back' (from Old English bæc) and 'side' (from Old English sīde), combining to mean simply 'the back side'. It has been used since Middle English, with early senses relating to the rear of things before settling into its familiar bodily meaning. Because it is a straightforward compound of common Germanic elements, it has no foreign cognates beyond those shared with the word 'back' itself.
How backside is actually used
Informal in tone when referring to the body. The 'rear of a building' sense is largely confined to British English and somewhat dated or regional there.
Easily confused with backside
'Behind' is primarily an adverb or preposition meaning 'at the back of', though it can also informally mean the buttocks; 'backside' is chiefly a noun referring to the buttocks or the rear of something.
'Backslide' is a verb meaning to revert to bad behaviour or a worse state, whereas 'backside' is a noun referring to the buttocks or the rear of something.