21-letter words containing y, a, m, o
- weinberg-salam theory — electroweak theory.
- william of malmesbury — William of, William of Malmesbury.
- yellow-rumped warbler — a common North American wood warbler, Dendroica coronata, having yellow spots on the rump, crown, and sides, including a white-throated eastern subspecies (myrtle warbler) and a yellow-throated western subspecies (Audubon's warbler)
- your mileage may vary — (jargon) (YMMV) The disclaimer American car manufacturers attached to EPA mileage ratings. A humourous way of saying that the thing under discussion will not necessarily give you the same results as the author. Often used to convey the hardware dependence of Unix freeware distributions.
- youth training scheme — (formerly, in Britain) a scheme, run by the Training Agency, to provide vocational training for unemployed 16–17-year-olds