20-letter words containing a, r, i, s
- aristarchus of samos — 3rd century bc, Greek astronomer who anticipated Copernicus in advancing the theory that the earth revolves around the sun
- artificial harmonics — harmonics of a note produced on a stringed instrument by lightly touching a stopped sounded string.
- artificial satellite — a man-made device orbiting around the earth, moon, or another planet transmitting to earth scientific information or used for communication
- artificial selection — a process in the breeding of animals and in the cultivation of plants by which the breeder chooses to perpetuate only those forms having certain desirable inheritable characteristics.
- as right as a trivet — in perfect health
- as straight as a die — perfectly honest
- asexual reproduction — reproduction, as budding, fission, or spore formation, not involving the union of gametes.
- asian tiger mosquito — a mosquito, Aedes albopictus, native to Asia, that transmits yellow fever and dengue and possibly West Nile virus. Compare yellow-fever mosquito.
- asset turnover ratio — An asset turnover ratio is a measure of the efficiency of a company, that is calculated by dividing sales for a period by average total assets.
- association of stars — a sparsely populated group of between 10 and 1000 young stars of similar spectral type and common origin that are moving too fast to form a permanent, gravitationally bound system.
- astatic galvanometer — a galvanometer that is unaffected by the earth's magnetic field and is used for measuring small currents.
- asymmetrical warfare — warfare between a powerful military force and a weak guerilla force
- at one's finger tips — the tip or end of a finger.
- at someone's service — ready to serve or cooperate with someone
- at two hours' notice — with notification only two hours in advance
- atmospheric pressure — Atmospheric pressure is the pressure of the atmosphere on the Earth's surface.
- attacks as a service — (security, legal) A kind of cybercrime as a service in which the service provider performs denial of service attacks on behalf of others for money.
- attic salt (or wit) — graceful, piercing wit
- 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.
- 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.
- backwards compatible — backward compatibility
- bacteriochlorophylls — Plural form of bacteriochlorophyll.
- 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.
- barred spiral galaxy — a spiral galaxy whose center has the form of an extended bar.
- bartramian sandpiper — upland sandpiper.
- basal cell carcinoma — a common and usually curable skin cancer that arises from epithelial cells and rarely metastasizes: often associated with overexposure to sunlight.
- 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 encoding rules — (protocol, standard) (BER) ASN.1 encoding rules for producing self-identifying and self-delimiting transfer syntax for data structures described in ASN.1 notations. BER is an self-identifying and self-delimiting encoding scheme, which means that each data value can be identified, extracted and decoded individually. Huw Rogers once described BER as "a triumph of bloated theory over clean implementation". He also criticises it as designed around bitstreams with arbitrary boundaries between data which can only be determined at a high level. Documents: ITU-T X.690, ISO 8825-1. See also CER, DER, PER.
- basic lead carbonate — ceruse.
- basic object adapter — (architecture) (BOA) Part of the CORBA architecture.
- basic oxygen process — a process for refining steel in which oxygen is blown into the molten iron
- 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
- beaverhead mountains — a mountain range on the border of E Idaho and SW Montana, in the Bitterroot Range. 10,961 feet (3343 meters).
- belgian shepherd dog — a medium-sized well-proportioned dog of a breed that resembles an Alsatian in appearance and is often used as a sheepdog or a guard dog
- 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
- bimodal distribution — a frequency distribution with two modes
- biological diversity — Biological diversity is the same as biodiversity.
- bird-footed dinosaur — theropod.
- bismarck archipelago — a group of over 200 islands in the SW Pacific, northeast of New Guinea: part of Papua New Guinea. Main islands: New Britain, New Ireland, Lavongai, and the Admiralty Islands. Chief town: Rabaul, on New Britain. Pop: 566 610 (2000). Area: 49 658 sq km (19 173 sq miles)
- 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)
- board of supervisors — the governing body of a county in many U.S. states, especially in the Midwest and the East, consisting of from 15 to 100 members elected from towns, townships, cities, or wards.
- bomb disposal expert — an expert in bomb disposal
- bone mineral density — a measurement of the amount of calcium and other minerals in a segment of bone, a higher mineral content indicating a higher bone density and strength, used to detect osteoporosis or monitor its treatment.
- born-again christian — person: evangelical
- bouvier des flandres — any of a breed of large, strong dog with a rough, wiry coat and pointed, erect ears