18-letter words containing i, p, r, o
- vigoureux printing — a printing method in which worsted fibers are printed with the desired color while in sliver form and then processed into yarn, producing a mixed color in the spun yarn and woven fabric.
- visiting professor — a professor from another institution invited to teach at a university or college for a limited period, usually for a semester or one academic year.
- visitor's passport — (formerly, in Britain) a passport, valid for one year and for certain countries only, that could be purchased from post offices
- warehouse capacity — the amount of storage space in a warehouse
- western isles pony — a breed of large pony, typically grey, with a dense waterproof coat. The only surviving variety is the Eriskay pony
- white iron pyrites — marcasite
- wild passionflower — the maypop, Passiflora incarnata.
- wildlife programme — (esp on television) a documentary whose subject is wild animals in their natural habitat or undomesticated fauna and flora generally
- wilson's phalarope — a phalarope, Phalaropus tricolor, that breeds in the prairie regions of North America and winters in Argentina and Chile.
- wireless telephone — Now Rare. radiotelephony.
- wireless telephony — Now Rare. radiotelephony.
- withdrawal symptom — effects of stopping a drug
- women at point sur — a narrative poem (1927) by Robinson Jeffers.
- working hypothesis — See under hypothesis (def 1).
- world championship — an international competition in a particular sport or activity for people all around the world
- zion national park — a park in SW Utah. 148 sq. mi. (383 sq. km).