16-letter words containing o, p, i, n, a
- transport police — the national police force for railways in Britain, which protects rail operators, staff and passengers
- trial separation — an experimental period of living apart
- tridarn cupboard — a Welsh cupboard of the late 17th and 18th centuries, with an open, canopied upper section for display.
- triple-expansion — noting a power source, especially a steam engine, using the same fluid at three successive stages of expansion to do work in three or more cylinders.
- tropic of cancer — Geography. either of two corresponding parallels of latitude on the terrestrial globe, one (tropic of Cancer) about 23½° N, and the other (tropic of Capricorn) about 23½° S of the equator, being the boundaries of the Torrid Zone. the tropics, the regions lying between and near these parallels of latitude; the Torrid Zone and neighboring regions.
- tropical cyclone — a cyclone that originates over a tropical ocean area and can develop into the destructive storm known in the U.S. as a hurricane, in the western Pacific region as a typhoon, and elsewhere by other names. Compare extratropical cyclone, hurricane (def 1), willy-willy.
- trucking company — a company that transports goods by lorry
- unaccomplishable — to bring to its goal or conclusion; carry out; perform; finish: to accomplish one's mission.
- unapologetically — containing an apology or excuse for a fault, failure, insult, injury, etc.: An apologetic letter to his creditors explained the delay.
- uncinate process — a curved, bony process on certain ribs of birds that projects backward and overlaps the succeeding rib, serving to strengthen the thorax.
- unimpressionable — easily impressed or influenced; susceptible: an impressionable youngster.
- unimproved value — the valuation of land for rating purposes, disregarding the value of buildings or other development
- unproportionally — having due proportion; corresponding.
- upside-down cake — a cake that is baked on a layer of fruit, then turned before serving so that the fruit is on top.
- upsilon particle — the 20th letter of the Greek alphabet (Υ, υ).
- vapor channeling — Vapor channeling exists when vapor flow is distributed in an unequal way in a distillation vessel or stage.
- vapor combustion — Vapor combustion is a closed burn system used for treating liquid waste which contains volatile organic compounds.
- ventriculography — radiography of the ventricles of the heart after injection of a contrast medium
- virginia cowslip — a perennial woodland plant (Mertensia virginica) of the borage family, native to E North America and having clusters of blue or purple, bell-shaped flowers
- white propaganda — propaganda that comes from the source it claims to come from
- willow ptarmigan — a ptarmigan, Lagopus lagopus, of arctic and subarctic regions of the New and Old Worlds, having brown, mottled plumage in summer and white plumage in winter.
- windfall profits — Windfall profits are excessive profits with a non-business cause such as a natural disaster.
- windowpane shell — capiz.
- wisconsin rapids — a city in central Wisconsin.
- writ of subpoena — a legal document commanding the attendance in court, as a witness, of the person on whom it is served, under a penalty
- yellow poinciana — royal poinciana.
- zygosporangium's — a sporangium that bears a zygospore.