18-letter words containing p, r, a, i, s
- property insurance — insurance coverage for land and housing
- proprietary rights — rights of ownership
- protease inhibitor — a drug that inhibits the action of protease, especially any of a class of antiviral drugs that prevent the cleavage and replication of HIV proteins.
- provascular tissue — procambium.
- provision merchant — a person or company in the business of retailing food and other provisions
- przewalski's horse — a wild horse, Equus caballus przevalskii, chiefly of Mongolia and Sinkiang, characterized by light yellow coloring and a stiff, upright black mane with no forelock: the only remaining breed of wild horse, it is now endangered and chiefly maintained in zoos.
- pseudo-anarchistic — a person who advocates or believes in anarchy or anarchism.
- psychotherapeutics — psychotherapy.
- pulmonary embolism — the blockage of a pulmonary artery, often by a blood clot, that stops the flow of blood to the lungs and which can result in death if untreated
- pulmonic airstream — a current of lung air set in motion by the respiratory muscles in the production of speech.
- purchasing officer — the member of staff in an organization who is responsible for buying goods or products
- pyramus and thisbe — (in Greek legend) two lovers of Babylon: Pyramus, wrongly supposing Thisbe to be dead, killed himself and she, encountering him in his death throes, did the same
- pyrosulphuric acid — a fuming liquid acid made by adding sulphur trioxide to concentrated sulphuric acid. Formula: H2S2O7
- qattara depression — a desert basin in the Libyan Desert, in NW Egypt: lowest point is 435 feet (133 meters) below sea level. 6950 sq. mi. (18,000 sq. km).
- radiation exposure — exposure to radiant energy or to the particles emitted in the transfer of radiant energy, esp the particles and gamma rays emitted in nuclear decay; exposure to radioactive substances
- radiation pressure — the pressure exerted on a surface by electromagnetic radiation or by sound waves.
- radical empiricism — (in the philosophy of William James) the doctrine that the only proper subject matter of philosophy is that which can be defined in terms of experience, and that relations are a part of experience.
- radical expression — an expression in which radical signs appear.
- rail rapid transit — a system of rail transit within an urban area that has exclusive right of way either below, above, or on the ground and so is capable of relatively high operating speed. Abbreviation: RRT.
- rape crisis centre — a place that provides support to people who have been victims of rape or other kinds of sexual abuse
- recess appointment — a person appointed to an office by the President of the United States without approval from the Senate because the Senate is in recess
- registered company — a company which has officially registered its business
- registration plate — a plate mounted on the front and back of a motor vehicle bearing the registration number
- regular expression — 1. (text, operating system) (regexp, RE) One of the wild card patterns used by Perl and other languages, following Unix utilities such as grep, sed, and awk and editors such as vi and Emacs. Regular expressions use conventions similar to but more elaborate than those described under glob. A regular expression is a sequence of characters with the following meanings (in Perl, other flavours vary): An ordinary character (not one of the special characters discussed below) matches that character. A backslash (\) followed by any special character matches the special character itself. The special characters are: "." matches any character except newline; "RE*" (where RE is any regular expression and the "*" is called the "Kleene star") matches zero or more occurrences of RE. If there is any choice, the longest leftmost matching string is chosen. "^" at the beginning of an RE matches the start of a line and "$" at the end of an RE matches the end of a line. (RE) matches whatever RE matches and \N, where N is a digit, matches whatever was matched by the RE between the Nth "(" and its corresponding ")" earlier in the same RE. Many flavours use \(RE\) instead of just (RE). The concatenation of REs is a RE that matches the concatenation of the strings matched by each RE. RE1 | RE2 matches whatever RE1 or RE2 matches. \< matches the beginning of a word and \> matches the end of a word. Many flavours use "\b" instead as the special character for "word boundary". RE{M} matches M occurences of RE. RE{M,} matches M or more occurences of RE. RE{M,N} matches between M and N occurences. Other flavours use RE\{M\} etc. Perl provides several "quote-like" operators for writing REs, including the common // form and less common ??. A comprehensive survey of regexp flavours is found in Friedl 1997 (see below). 2. Any description of a pattern composed from combinations of symbols and the three operators: Concatenation - pattern A concatenated with B matches a match for A followed by a match for B. Or - pattern A-or-B matches either a match for A or a match for B. Closure - zero or more matches for a pattern. The earliest form of regular expressions (and the term itself) were invented by mathematician Stephen Cole Kleene in the mid-1950s, as a notation to easily manipulate "regular sets", formal descriptions of the behaviour of finite state machines, in regular algebra.
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- representativeness — a person or thing that represents another or others.
- reprocessing plant — a plant where materials are treated in order to make them reusable
- resistance plasmid — any of a group of bacterial plasmids carrying genetic information that provide resistance to antibiotic drugs: some resistance plasmids are able to transfer themselves, and hence resistance, during conjugation
- respiratory arrest — cessation of breathing
- respiratory system — the system by which oxygen is taken into the body and an exchange of oxygen and carbon dioxide takes place; in mammals the system includes the nasal passages, pharynx, trachea, bronchi, and lungs.
- resurrection plant — a desert plant, Selaginella lepidophylla, occurring from Texas to South America, having stems that curl inward when dry.
- 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.
- saint bernard pass — either of two passes over the Alps: the Great St Bernard Pass 2472 m (8110 ft) high, east of Mont Blanc between Italy and Switzerland, or the Little St Bernard Pass 2157 m (7077 ft) high, south of Mont Blanc between Italy and France
- saint peter's fish — another name for tilapia, taken from a Bible story about Saint Peter catching a fish with a coin in its mouth
- sampling frequency — sample rate
- scholarship holder — a person who, because of academic merit, receives financial aid for their studies
- scissors-and-paste — designating or of a piece of writing that has been assembled from a variety of sources rather than by original research, often in a hasty or uninspired way
- scripting language — a language that is used to write scripts, or executable sections of code that automate tasks.
- 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.
- seasonal promotion — Seasonal promotions are items marketed to customers at the appropriate time of year, such as coats in the winter and bathing suits in the summer.
- secondary syphilis — the second stage of syphilis, characterized by eruptions of the skin and mucous membrane.
- self-deprecatingly — in a self-deprecating manner
- self-disparagement — the act of disparaging.
- self-preoccupation — the state of being preoccupied.
- self-tapping screw — a screw designed to tap its corresponding female thread as it is driven.
- separation anxiety — the normal fear and apprehension expressed by infants when removed from their mothers or approached by strangers.
- september holidays — a period of time in September when people do not have to go to school, college or work
- septic sore throat — an acute, toxic, streptococcus infection of the throat producing fever, tonsillitis, and other serious effects.
- service department — a repair shop
- sharp-shinned hawk — a North American hawk, Accipiter striatus, having extremely slender legs, a bluish-gray back, and a white, rusty-barred breast.