21-letter words containing p, e, r, i, n
- psychoneuroimmunology — the study of the effects of psychological factors on the immune system
- public-key encryption — (cryptography) (PKE, Or "public-key cryptography") An encryption scheme, introduced by Diffie and Hellman in 1976, where each person gets a pair of keys, called the public key and the private key. Each person's public key is published while the private key is kept secret. Messages are encrypted using the intended recipient's public key and can only be decrypted using his private key. This is often used in conjunction with a digital signature. The need for sender and receiver to share secret information (keys) via some secure channel is eliminated: all communications involve only public keys, and no private key is ever transmitted or shared. Public-key encryption can be used for authentication, confidentiality, integrity and non-repudiation. See also knapsack problem.
- pulse height analyser — a multichannel analyser that sorts pulses into selected amplitude ranges
- pulse height analyzer — an instrument that records or counts an electrical pulse if its amplitude falls within specified limits: used in nuclear physics research for the determination of energy spectra of nuclear radiations
- purchasing department — the group of staff within an organization that is responsible for buying goods or products
- pure imaginary number — a complex number of the form iy where y is a real number and i = .
- purple-fringed orchid — either of two orchids, Habenaria fimbriata or H. psycodes, of eastern North America, having a cluster of fragrant purple flowers with a fringed lip.
- purple-fringed orchis — either of two North American orchids (Habenaria psycodes and H. fimbriata) with purple-fringed flowers
- put in the hard yards — to make a great effort to achieve an end
- put sb in the picture — If you put someone in the picture, you tell them about a situation which they need to know about.
- put sb in their place — If you put someone in their place, you show them that they are less important or clever than they think they are.
- put something over on — to deceive; trick
- pyrenean mountain dog — a large heavily built dog of an ancient breed originally used to protect sheep from wild animals: it has a long thick white coat with a dense ruff
- quality point average — grade point average.
- quantum teleportation — a hypothetical technique to instantly transfer properties from one quantum system to another without contact, or to transfer a quantum state to an arbitrarily distant location.
- queer someone's pitch — to upset someone's plans
- reading comprehension — a text that students use to help them improve their reading skills, by reading it and answering questions relating to the text. Sometimes used as a test or examination of reading skills. A reading comprehension can be in the student's own or another language
- real operating system — (operating system, abuse) The sort the speaker is used to. People from the BSDophilic academic community are likely to issue comments like "System V? Why don't you use a *real* operating system?", people from the commercial/industrial Unix sector are known to complain "BSD? Why don't you use a *real* operating system?", and people from IBM object "Unix? Why don't you use a *real* operating system?" See holy wars, religious issues, proprietary, Get a real computer!.
- reciprocal inhibition — the theory that the pairing of an anxiety-provoking stimulus with anxiety-reducing reactions will weaken the association between the stimulus and the anxiety.
- recompression chamber — hyperbaric chamber.
- reconnaissance patrol — a patrol made by soldiers in order to obtain military information about a particular place
- recurrent expenditure — ongoing expenditure of an organization, such as salaries and travelling expenses
- redwood national park — a national park in N California: redwood forest with some of the world's tallest trees. 172 sq. mi. (445 sq. km).
- reinforcement therapy — a behavior modification technique in which appropriate behavior is strengthened through systematic reinforcement.
- repatriation expenses — Repatriation expenses are the costs involved in transporting a claimant or their body back to their own country after they have been injured or killed in a foreign country.
- replacement algorithm — The method used to determine which entry in an associative cache to flush to main memory when it is desired to cache a new block of data. The "least recently used" algorithm flushed the block which has not been accessed for the longest time. A random replacement algorithm picks any block with equal probability.
- residual unemployment — the unemployment that remains in periods of full employment, as a result of those mentally, physically, or emotionally unfit to work
- return from interrupt — (programming) (RTI) An instruction mnemonic on many computers including the 6502 and 6800. The variant "RETI" is found among former Zilog Z80 hackers (almost nobody programs these things in assembly code anymore). The Intel 80x86 equivalent is "IRET".
- return the compliment — repay sb's kindness with a kind act
- reverse polish syntax — postfix notation
- reverse transcriptase — a retrovirus enzyme that synthesizes DNA from viral RNA, the reverse of the usual DNA-to-RNA replication: used in genetic engineering to clone genes from RNA strands.
- roll with the punches — a thrusting blow, especially with the fist.
- sanitation department — the department of local government responsible for collecting and disposing of refuse
- sao tome and principe — Democratic Republic of, a republic in W Africa, comprising the islands of São Tomé and Príncipe, in the Gulf of Guinea, N of the equator: a former overseas province of Portugal; gained independence in 1975. 372 sq. mi. (964 sq. km). Capital: São Tomé.
- saponification number — the number of milligrams of potassium hydroxide required to saponify one gram of a given ester, especially a glyceride.
- sb/sth reigns supreme — Someone or something that reigns supreme is the most important or powerful element in a situation or period of time.
- schlieren photography — a type of photography which records schlieren
- school superintendent — an official whose job is to oversee school administration within a district
- schoolgirl complexion — a smooth, clear complexion, such as schoolgirls are considered to have
- science correspondent — a newspaper or television journalist who specializes in reporting on new discoveries in science
- scientific empiricism — the philosophy that there are no real differences between the sciences.
- sequoia national park — a national park in central California: giant sequoia trees. 604 sq. mi. (1565 sq. km).
- sheppard's correction — a method of correcting the bias in standard deviations and higher moments of distributions that arises from grouping values of the variable.
- shut-in pressure test — A shut-in pressure test is a pressure test which is carried out after the well has been closed off for a particular time.
- simple actor language — (language) (SAL) A minimal actor language, used for teaching in:
- sing for one's supper — to obtain something by performing a service
- single parent benefit — a form of government funded financial assistance paid to single parents
- single spanish burton — a tackle having a runner as well as the fall supporting the load, giving a mechanical advantage of three, neglecting friction.
- sinusoidal projection — an equal-area projection in which parallels are straight lines spaced at regular intervals, the central meridian is a straight line one-half the length of the equator, and the other meridians are curves symmetrical to the central meridian.
- skop, skiet en donder — violent action and melodramatic adventure in a film