18-letter words containing p, i, w
- self-tapping screw — a screw designed to tap its corresponding female thread as it is driven.
- sharp-shinned hawk — a North American hawk, Accipiter striatus, having extremely slender legs, a bluish-gray back, and a white, rusty-barred breast.
- silvery spleenwort — a fern, Diplazium pycnocarpon, of eastern North America, having fronds from 20 to 30 inches (50.8 to 76.2 cm) long on yellowish-green stalks.
- slow-motion replay — a showing again in slow motion of a sequence of action, esp of part of a sporting contest immediately after it happens
- spike-tooth harrow — a harrow equipped with straight teeth on horizontal bars, usually employed to smooth and level plowed soil or seedbeds for planting or sowing.
- spread one's wings — to make full use of one's abilities
- super middleweight — a boxer weighing up to 168 pounds (75.6 kg), between middleweight and light heavyweight.
- sweptwing aircraft — an aircraft which has wings that are swept (usually) backwards
- talk between ships — TBS (def 1).
- the operative word — If you describe a word as the operative word, you want to draw attention to it because you think it is important or exactly true in a particular situation.
- traditional weapon — a weapon having ceremonial tribal significance, such as an assegai or knobkerrie
- warehouse capacity — the amount of storage space in a warehouse
- weberian apparatus — (in certain fishes) a chain of small bones and ligaments connecting the inner ear with the air bladder.
- welland ship canal — a ship canal in S Canada, in Ontario, connecting Lakes Erie and Ontario: 8 locks. 25 miles (40 km) long.
- wernicke's aphasia — a type of aphasia caused by a lesion in Wernicke's area of the brain and characterized by grammatical but more or less meaningless speech and an apparent inability to comprehend speech.
- western hemisphere — the western part of the terrestrial globe, including North and South America, their islands, and the surrounding waters.
- western isles pony — a breed of large pony, typically grey, with a dense waterproof coat. The only surviving variety is the Eriskay pony
- whispering gallery — a space or gallery beneath a dome or broad arch in which low sounds produced at any of certain points are clearly audible at certain other distant points.
- white iron pyrites — marcasite
- white trumpet lily — a lily, Lilium longiflorum, of Japan, having fragrant, pure white, trumpet-shaped flowers nearly 7 inches (18 cm) in length.
- white-spotted hyla — a type of tree frog (H. leucophyllata) of tropical America
- 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