18-letter words containing p, r, o, v, a
- prepositional verb — a combination of verb and preposition, often with idiomatic meaning, differing from other phrasal verbs in that an object must always follow the preposition, as take after in The children take after their mother.
- preservation order — In Britain, a preservation order is an official order that makes it illegal for anyone to alter or destroy something such as an old building or an area of countryside.
- provably difficult — The set or property of problems for which it can be proven that no polynomial-time algorithm exists, only exponential-time algorithms.
- provascular tissue — procambium.
- provincial council — (formerly) a council administering any of the New Zealand provinces
- provision merchant — a person or company in the business of retailing food and other provisions
- psychogalvanometer — a type of galvanometer for detecting and measuring psychogalvanic currents.
- rapid eye movement — rapidly shifting, continuous movements of the eyes beneath closed lids during the stage of sleep characterized by dreaming.
- reactive component — the component in an alternating-current circuit that does not contribute power because it is 90° out of phase with the voltage or current.
- recovery operation — the process of locating and retrieving bodies, esp following an explosion or natural disaster
- redevelopment area — an urban area in which all or most of the buildings are demolished and rebuilt
- sodium-vapour lamp — a type of electric lamp consisting of a glass tube containing neon and sodium vapour at low pressure through which an electric current is passed to give an orange light. They are used in street lighting
- super royal octavo — a book size, 63⁄4 by 101⁄4 inches
- superior vena cava — See under vena cava.
- supportive therapy — any treatment, such as the intravenous administration of certain fluids, designed to reinforce or sustain the physiological well-being of a patient
- surveyor's compass — an instrument used by surveyors for measuring azimuths.
- 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.
- to play favourites — to display favouritism
- to scrape a living — If you say that someone scrapes a living or scratches a living, you mean that they manage to earn enough to live on, but it is very difficult. In American English, you say they scrape out a living or scratch out a living.
- transverse process — a process that projects from the sides of a vertebra.
- universal coupling — a coupling between rotating shafts set at an angle to one another, allowing for rotation in three planes.
- vectorcardiography — a method of determining the direction and magnitude of the electrical forces of the heart.
- vermiform appendix — a narrow, blind tube protruding from the cecum, having no known useful function, in humans being 3 to 4 inches (8 to 10 cm) long and situated in the lower right-hand part of the abdomen.
- videotape recorder — a device for recording television programs on magnetic tape for delayed transmission or for storage.
- visitor's passport — (formerly, in Britain) a passport, valid for one year and for certain countries only, that could be purchased from post offices