18-letter words containing p, a, d, l, e, o
- put a bold face on — to seem bold or confident about
- pyromucic aldehyde — furfural.
- quartz-iodine lamp — a type of tungsten-halogen lamp containing small amounts of iodine and having a quartz envelope, operating at high temperature and producing an intense light for use in car headlamps, etc
- radical expression — an expression in which radical signs appear.
- redevelopment area — an urban area in which all or most of the buildings are demolished and rebuilt
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- rhodes scholarship — one of a number of scholarships at Oxford University, established by the will of Cecil Rhodes, for selected students (Rhodes scholars) from the British Commonwealth and the United States.
- scholarship holder — a person who, because of academic merit, receives financial aid for their studies
- seafloor spreading — a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
- secondary syphilis — the second stage of syphilis, characterized by eruptions of the skin and mucous membrane.
- september holidays — a period of time in September when people do not have to go to school, college or work
- soda-lime feldspar — plagioclase.
- solitary sandpiper — a North American sandpiper, Tringa solitaria, of inland wetlands, having a brownish-gray, white-spotted back and whitish underparts.
- spotted flycatcher — a European woodland songbird, Muscicapa striata, with a greyish-brown streaked plumage: family Muscicapidae (Old World flycatchers)
- supraorbital ridge — browridge.
- the lords temporal — (in Britain) peers other than bishops in their capacity as members of the House of Lords
- to hold your peace — If you hold or keep your peace, you do not speak, even though there is something you want or ought to say.
- traditional weapon — a weapon having ceremonial tribal significance, such as an assegai or knobkerrie
- 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