In British English, the green space attached to a house is the garden, planted or not: "the kids are in the back garden". In American English that space is the yard, and garden means specifically a cultivated bed of flowers or vegetables: "mow the yard", "tomatoes from the garden". Same patch of grass, different word depending on where you are.
The core difference
This is a dialect split, not a rule about meaning, and it is the single most reliable giveaway of which side of the Atlantic a writer is on.
British English: garden is the whole outdoor area belonging to a house — lawn, patio, borders, shed. Yard means a hard-surfaced enclosed space with no planting: a builder's yard, a school yard, the paved back yard of a terraced house.
American English: yard is the whole outdoor area, typically lawn. Garden is the part you actually grow things in — a vegetable garden, a flower garden.
How to use each
- British: "We're having drinks in the garden." "He's mowing the lawn." "They store the pallets in the yard round the back."
- American: "The kids are playing in the yard." "I need to mow the yard." "She grows squash in the garden behind the fence."
The test that settles it
Ask two questions: who is reading, and is anything growing there deliberately?
Writing for Britons: use garden for the space by default; only use yard if it is paved and functional. Writing for Americans: use yard for the space by default; only use garden for the planted part.
Phrases that reveal the split
- Back garden (UK) / backyard (US) — note the US version is usually one word.
- Front garden (UK) / front yard (US).
- Car boot sale (UK) / yard sale or garage sale (US).
- Garden centre (UK) / garden center or nursery (US) — both use garden.
- Gardening — universal. Nobody says "yarding", though Americans do say yard work.
The other yard
Yard is also a unit of length, three feet or 0.9144 metres, in every variety of English. And in nautical use it is the spar that holds a sail. Neither meaning has anything to do with land around a house, but context always makes it clear.
Where both work
Some compounds are shared. Churchyard, courtyard, graveyard, shipyard, scrapyard and railway yard use yard on both sides, because they are all enclosed working or paved spaces — the older British sense. Garden party, walled garden, roof garden and botanical garden are equally universal.