20-letter words containing a, t
- attendance allowance — (in Britain) a tax-free noncontributory welfare benefit for people over 65 years old who are so severely disabled that they need frequent attention or continual supervision for a period of six months or more
- attic salt (or wit) — graceful, piercing wit
- audio-lingual method — a technique of foreign-language instruction that emphasizes audio-lingual skills over reading and writing and is characterized by extensive use of pattern practice.
- australian rye grass — a European grass, Lolium multiflorum, naturalized in North America, having flowering spikes and used as a winter turf.
- automobile insurance — Automobile insurance is insurance coverage for cars.
- auxiliary power unit — an additional engine fitted to an aircraft to operate when the main engines are not in use
- axiomatic set theory — (theory) One of several approaches to set theory, consisting of a formal language for talking about sets and a collection of axioms describing how they behave. There are many different axiomatisations for set theory. Each takes a slightly different approach to the problem of finding a theory that captures as much as possible of the intuitive idea of what a set is, while avoiding the paradoxes that result from accepting all of it, the most famous being Russell's paradox. The main source of trouble in naive set theory is the idea that you can specify a set by saying whether each object in the universe is in the "set" or not. Accordingly, the most important differences between different axiomatisations of set theory concern the restrictions they place on this idea (known as "comprehension"). NBG (von Neumann-Bernays-Goedel) set theory sort of allows comprehension for all formulae without restriction, but distinguishes between two kinds of set, so that the sets produced by applying comprehension are only second-class sets. NBG is exactly as powerful as ZF, in the sense that any statement that can be formalised in both theories is a theorem of ZF if and only if it is a theorem of ZFC. MK (Morse-Kelley) set theory is a strengthened version of NBG, with a simpler axiom system. It is strictly stronger than NBG, and it is possible that NBG might be consistent but MK inconsistent. ML ("Modern Logic") is to NF as NBG is to ZF. (Its name derives from the title of the book in which Quine introduced an early, defective, form of it). It is stronger than ZF (it can prove things that ZF can't), but if NF is consistent then ML is too.
- babylonian captivity — the exile of the Jews in Babylonia from about 586 to about 538 bc
- baccalaureate sermon — a farewell sermon addressed to a graduating class in some U.S. colleges and schools.
- back the wrong horse — to bet on a horse that loses the race
- back-of-the-envelope — (of a plan, calculation, etc) composed or performed quickly and without detailed analysis or research
- background radiation — low-intensity radiation from, for example, small amounts of radioisotopes in soil, air, building materials, etc
- backwards compatible — backward compatibility
- bacteriochlorophylls — Plural form of bacteriochlorophyll.
- baggage storage room — A baggage storage room is a room in a hotel where people can leave their baggage in order to collect it later.
- balanced three-phase — A balanced three-phase voltage or current is one in which the size of each phase is the same, and the phase angles of the three phases differ from each other by 120 degrees.
- ballet-wrap cardigan — a cardigan with wrapover fronts which are fastened with wraparound ties
- ballistic trajectory — the path of an unpowered object, as a missile, moving only under the influence of gravity and possibly atmospheric friction and with its surface providing no significant lift to alter the course of flight.
- baptism for the dead — the baptism of a living person in the place of and for the sake of one who has died unbaptized: now practiced chiefly by Mormons.
- barothermohygrograph — an automatic instrument for recording pressure, temperature, and humidity.
- bartramian sandpiper — upland sandpiper.
- basal metabolic rate — the rate at which heat is produced by the body at rest, 12 to 14 hours after eating, measured in kilocalories per square metre of body surface per hour
- basic lead carbonate — ceruse.
- basic object adapter — (architecture) (BOA) Part of the CORBA architecture.
- basic rate interface — (communications) (BRI, 2B+D, 2B1D) An Integrated Services Digital Network channel consisting of two 64 kbps "bearer" (B) channels and one 16 kbps "delta" (D) channel, giving a total data rate of 144 kbps. The B channels are used for voice or user data, and the D channel is used for control and signalling and/or X.25 packet networking. BRI is the kind of ISDN interface most likely to be found in residential service.
- bats-wing coral-tree — a small tree, Erythrina verspertilio, of tropical and subtropical Australia with red flowers and leaves shaped like the wings of a bat
- be called to the bar — to become a barrister
- be hard pushed to do — If you are hard pushed to do something, you find it very difficult to do it.
- be in the market for — to wish to buy or acquire
- be set in one's ways — If you say that someone is set in their ways, you are being critical of the fact that they have fixed habits and ideas which they will not easily change, even though they may be old-fashioned.
- be-twixt and between — betwixt and between, neither the one nor the other; in a middle or unresolved position: Not wanting to side with either her father or her mother, she was betwixt and between.
- beat around the bush — to talk around a subject without getting to the point
- beat the shit out of — to give a severe beating to
- beaverhead mountains — a mountain range on the border of E Idaho and SW Montana, in the Bitterroot Range. 10,961 feet (3343 meters).
- been-there done-that — an exclamation expressing familiarity and boredom with a situation, experience, etc
- benavente y martinez — Jacinto. 1866–1954, Spanish dramatist and critic, who wrote over 150 plays. Nobel prize for literature 1922
- benoit b. mandelbrot — Benoit Mandelbrot
- benztropine mesylate — a synthetic anticholinergic, C 21 H 25 NO⋅CH 4 O 3 S, used in the treatment of Parkinson's disease.
- benzyl isoamyl ether — a colorless liquid, C 12 H 18 O, used in soap perfumes.
- bernese mountain dog — a strong sturdy dog of a breed with a bushy tail and a long silky black coat with reddish-brown and white markings, often used as a working farm dog
- bigmouth buffalofish — a buffalofish, Ictiobus cyprinellus, found in central North America, characterized by a large mouth.
- bimodal distribution — a frequency distribution with two modes
- binomial coefficient — any of the numerical factors which multiply the successive terms in a binomial expansion; any term of the form n!/(n–k)!k!: written (nk), nCk, or Cnk
- biological diversity — Biological diversity is the same as biodiversity.
- bird-footed dinosaur — theropod.
- black-throated diver — a diving bird, Gavia arctica, found in Europe and Asia, and a rare summer visitor to the UK
- blast-furnace cement — a type of cement made from a blend of ordinary Portland cement and crushed slag from a blast furnace. It has lower setting properties than ordinary Portland cement
- blending inheritance — the blending of characteristics of the parents in the offspring, as in a pink flower that results from the mating of a red flower with a white one
- blue ridge mountains — a mountain range in the eastern US, extending from West Virginia into Georgia: part of the Appalachian mountains. Highest peak: Mount Mitchell, 2038 m (6684 ft)
- blue screen of death — (humour) (BSOD) The infamous white-on-blue text screen which appears when Microsoft Windows crashes. BSOD is mostly seen on the 16-bit systems such as Windows 3.1, but also on Windows 95 and apparently even under Windows NT 4. It is most likely to be caused by a GPF, although Windows 95 can do it if you've removed a required CD-ROM from the drive. It is often impossible to recover cleanly from a BSOD. The acronym BSOD is sometimes used as a verb, e.g. "Windoze just keeps BSODing on me today".