20-letter words containing a, c, h
- ring-necked pheasant — a gallinaceous Asian bird, Phasianus colchicus, having a white band around its neck, introduced into Great Britain, North America, and the Hawaiian Islands.
- rise to the occasion — to have the courage, wit, etc, to meet the special demands of a situation
- rocky mountain sheep — bighorn.
- saint john ambulance — an organization that provides first aid and first-aid training
- sarcastic fringehead — any fish of the genus Neoclinus, characterized by a row of fleshy processes on the head, as N. blanchardi (sarcastic fringehead) of California coastal waters.
- satellite chromosome — a type of densely staining chromosome of uncertain biological function, found in many plant and animal species.
- saxe-weimar-eisenach — a former grand duchy in Thuringia in central Germany.
- scatter site housing — public housing, especially for low-income families, built throughout an urban area rather than being concentrated in a single neighborhood.
- scavenger's daughter — an instrument of torture that doubled over and squeezed the body so strongly and violently that blood was brought forth from the ears and nose: invented in 16th-century England.
- schizoid personality — sb with identity disorder
- school without walls — a nontraditional educational program that uses community facilities as learning resources.
- schrodinger equation — the wave equation of nonrelativistic quantum mechanics. Also called Schrödinger wave equation. Compare wave equation (def 2).
- schwarzschild radius — the radius at which a gravitationally collapsing celestial body becomes a black hole.
- schwarzschild sphere — the sphere which surrounds a non-rotating uncharged black hole, from within which no information can escape because of gravitational forces
- scottish nationalism — a political ideology advocating the independence of Scotland
- season ticket holder — a person who has a season ticket
- second-hand bookshop — a shop selling second-hand books
- sellers screw thread — a thread form in a system of standard sizes proposed by Sellers in 1884 and later accepted as standard in the USA, having a 60° flank angle with a flat top and foot
- semiautobiographical — pertaining to or being a fictionalized account of an author's own life.
- settle accounts with — to pay or receive a balance due
- sex change operation — a surgical operation designed to change a person's physical sexual characteristics to those of the opposite sex
- shifting cultivation — a land-use system, esp in tropical Africa, in which a tract of land is cultivated until its fertility diminishes, when it is abandoned until this is restored naturally
- short back and sides — If a man has a short back and sides, his hair is cut very short at the back and sides with slightly thicker, longer hair on the top of the head.
- silicon tetrahydride — silane (def 1).
- skating championship — a competition for ice-skating
- south american plate — a major tectonic division of the earth's crust, comprising the continent of South America and several ocean basins and bounded on the north by the Caribbean Plate, on the east by the Mid-Atlantic Ridge, on the west by a submarine trench that borders the western coast of the continent, and on the south by the Antarctic Plate.
- south atlantic ocean — the part of the Atlantic Ocean extending S from the Equator to the Antarctic continent.
- southern oscillation — a low-latitude fluctuation of atmospheric pressure closely linked with El Niño events, specifically the periods of El Niño warming and La Niña cooling.
- spanish west african — of or relating to the former Spanish overseas territory of Spanish West Africa (now the overseas provinces of Ifni and Spanish Sahara) or its inhabitants
- spanish-american war — the war between the U.S. and Spain in 1898.
- spatial technologies — (company) Distributors of the ACIS solid modelling engine.
- special relationship — the exceptionally close political, diplomatic, cultural and historical relations between the United States and the United Kingdom
- spherical aberration — variation in focal length of a lens or mirror from center to edge, due to its spherical shape.
- spherical coordinate — Usually, spherical coordinates. any of three coordinates used to locate a point in space by the length of its radius vector and the angles this vector makes with two perpendicular polar planes.
- spiral of archimedes — a curve that is the locus of a point that moves outward with uniform speed along a vector, beginning at the origin, while the vector rotates about the origin with uniform angular velocity. Equation (in polar coordinates): r = aθ.
- splice the mainbrace — to issue and partake of an extra allocation of alcoholic spirits
- st. george's channel — a channel between Wales and Ireland, connecting the Irish Sea and the Atlantic. 100 miles (160 km) long; 50–90 miles (81–145 km) wide.
- stallman, richard m. — Richard Stallman
- stare sb in the face — If a situation or the answer to a problem is staring you in the face, it is very obvious, although you may not be immediately aware of it.
- states of the church — Papal States
- step into the breach — If you step into the breach, you do a job or task which someone else was supposed to do or has done in the past, because they are suddenly unable to do it.
- stochastic terrorism — the public demonization of a person or group resulting in the incitement of a violent act, which is statistically probable but whose specifics cannot be predicted: The lone-wolf attack was apparently influenced by the rhetoric of stochastic terrorism.
- stoichiometric ratio — The stoichiometric ratio is the exact ratio between air and flammable gas or vapor at which complete combustion takes place.
- straight-cut tobacco — tobacco that is cut in such a way that it will lie flat.
- switchboard operator — a person who operates an installation in a telephone exchange, office, hotel, etc, at which the interconnection of telephone lines is manually controlled
- synchronized skating — the art or sport of teams of up to twenty skaters holding onto each other and moving in patterns in time to music
- synchronous rotation — rotation of a satellite in which the period of rotation is equal to the period of orbit around its primary, leaving the same face always pointing toward the primary: The moon is in synchronous rotation about the earth.
- take to the cleaners — a person who cleans, especially one whose regular occupation is cleaning offices, buildings, equipment, etc.
- tchebycheff equation — a differential equation of the form (1 − x 2) d 2 y/dx 2 − x dy/dx + n 2 y = 0, where n is any nonnegative integer.
- technology agreement — a framework designed by trade unions for negotiating changes in employment caused by the introduction of new technology