18-letter words containing r, a, t, i, f
- provably difficult — The set or property of problems for which it can be proven that no polynomial-time algorithm exists, only exponential-time algorithms.
- quality of service — (communications, networking) (QoS) The performance properties of a network service, possibly including throughput, transit delay, priority. Some protocols allow packets or streams to include QoS requirements.
- quarry-tiled floor — a floor covered with square or diamond-shaped unglazed floor tiles
- quarterlife crisis — a crisis that may be experienced in one's twenties, involving anxiety over the direction and quality of one's life
- quick off the mark — If you are quick off the mark, you are quick to understand or respond to something. If you are slow off the mark, you are slow to understand or respond to something.
- rabbit's-foot fern — hare's-foot fern.
- rabbit-foot clover — a plant, Trifolium arvense, having trifoliate leaves with narrow leaflets and fuzzy, cylindrical, grayish-pink flower heads.
- rabbit-proof fence — a fence through which rabbits are unable to pass
- radiant efficiency — the ratio of the power emitted by a source of radiation to the power consumed by it
- radius of gyration — the distance from an axis at which the mass of a body may be assumed to be concentrated and at which the moment of inertia will be equal to the moment of inertia of the actual mass about the axis, equal to the square root of the quotient of the moment of inertia and the mass.
- raffinate recovery — Raffinate recovery is the use of a substance which is left after a process is complete and the desired substances have been removed.
- range of stability — the angle to the perpendicular through which a vessel may be heeled without losing the ability to right itself.
- reaction formation — a behavioral tendency developed in direct opposition to a repressed impulse.
- real-estate office — the place where a real-estate agent works
- refrigerated lorry — a lorry which is chilled in the back as for storing food
- reinforced plastic — plastic with fibrous matter, such as carbon fibre, embedded in it to confer additional strength
- relative frequency — the ratio of the number of times an event occurs to the number of occasions on which it might occur in the same period.
- resistance fighter — someone who fights (for freedom, etc) against an invader in an occupied country, or against their government, etc, often secretly or illegally
- restraint of trade — action tending to interrupt the free flow of goods and services, as by price fixing and other practices that have the effect of reducing competition.
- russian federation — a republic extending from E Europe to N and W Asia. 6,593,000 sq. mi. (17,076,000 sq. km). Capital: Moscow.
- sacrificial victim — a person who is ritually killed with the intention of propitiating or pleasing a deity
- safety regulations — regulations or rules that are put in place to ensure a product, event, etc, is safe and not dangerous
- 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
- school certificate — (in England and Wales between 1917 and 1951 and currently in New Zealand) a certificate awarded to school pupils who pass a public examination: the equivalent of GCSE
- self-advertisement — a paid announcement, as of goods for sale, in newspapers or magazines, on radio or television, etc.
- self-certification — statement of sick leave
- self-contradiction — an act or instance of contradicting oneself or itself.
- self-contradictory — an act or instance of contradicting oneself or itself.
- self-deprecatingly — in a self-deprecating manner
- self-determination — determination by oneself or itself, without outside influence.
- self-disparagement — the act of disparaging.
- self-entertainment — the act of entertaining; agreeable occupation for the mind; diversion; amusement: Solving the daily crossword puzzle is an entertainment for many.
- self-fertilization — Botany. fertilization of an ovum of a plant by a male gamete from the same flower (opposed to cross-fertilization).
- self-glorification — a glorified or more splendid form of something.
- self-gratification — the act of pleasing or satisfying oneself, especially the gratifying of one's own impulses, needs, or desires.
- self-incriminating — serving to incriminate oneself or to expose oneself to prosecution: self-incriminating testimony.
- self-incrimination — the act of incriminating oneself or exposing oneself to prosecution, especially by giving evidence or testimony.
- self-instructional — pertaining to or constituting learning materials and conditions arranged so that students can proceed to learn on their own with little or no supervision.
- self-interrogation — the act of interrogating; questioning.
- self-mortification — the inflicting of pain or privation on oneself: He was certain that self-mortification was the only road to salvation.
- self-preoccupation — the state of being preoccupied.
- self-recrimination — the act of recriminating, or countercharging: Hope gave way to recrimination with both sides claiming the moral high ground.
- self-tapping screw — a screw designed to tap its corresponding female thread as it is driven.
- self-understanding — mental process of a person who comprehends; comprehension; personal interpretation: My understanding of the word does not agree with yours.
- senior aircraftman — a rank in the Royal Air Force comparable to that of a private in the army, though not the lowest rank in the Royal Air Force
- sildenafil citrate — a white crystalline powder, C 22 H 30 N 6 O 4 S, that temporarily normalizes erectile function of the penis by blocking an enzyme known to inhibit the production of a chemical that causes erections: used in the form of a pill to treat impotence.
- silver certificate — a former paper currency first issued in 1878 by the U.S. federal government for circulation, equal to and redeemable for silver to a stated value.
- skin friction drag — aerodynamic resistance or drag due to the contact of moving air with the surface of an airplane, a glider, etc.
- spirits of ammonia — a 10% solution of ammonia in alcohol
- standard of living — a grade or level of subsistence and comfort in everyday life enjoyed by a community, class, or individual: The well-educated generally have a high standard of living.