Trousers is the standard British word for the leg garment worn over the waist to the ankles, while pants is the standard American word for the same thing. In Britain, though, pants usually means underwear, so use trousers to avoid confusion when writing for a British reader.
The core difference
Trousers and pants refer to the same outer leg garment, but in British English pants normally means underwear instead.
- trousers — an outer garment covering the waist to the ankles, with a separate section for each leg: He ironed his trousers before the interview.
- pants — the standard American word for the same outer garment: He bought a new pair of pants for the interview. In British English it more often means underwear: She pulled on a clean pair of pants before getting dressed.
How to tell them apart
The safest rule is to think about audience rather than garment. If you are writing in British English, trousers is the unambiguous word for the outer garment, since a British reader will hear pants and picture underwear first. If you are writing in American English, pants is the natural, everyday word, and trousers can sound slightly formal or old-fashioned.
British English also uses pants informally as slang for something disappointing or poor quality, such as saying a film was absolute pants, which has nothing to do with clothing at all.
