21-letter words containing a, w, y
- water-vascular system — a system of closed, fluid-filled tubes and ducts of echinoderms used in clinging, locomotion, feeding, and respiration.
- weinberg-salam theory — electroweak theory.
- west university place — a city in SE Texas.
- william of malmesbury — William of, William of Malmesbury.
- yellow lady's-slipper — a showy orchid, Cypripedium calceolus, of eastern North America, having purple-tinged yellow flowers with an inflated lip petal.
- 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)
- yellow-throated vireo — an olive-green vireo, Vireo flavifrons, of eastern North America, having a bright yellow throat and breast.