21-letter words containing a, c, i, d
- strategic air command — a U.S. Air Force command charged with intercontinental air strikes, especially nuclear attacks.
- student participation — the extent to which students participate or involve themselves in a class, course, etc
- submerged arc welding — a type of heavy electric-arc welding using mechanically fed bare wire with the arc submerged in powdered flux to keep out oxygen
- suction and curettage — a technique involving extraction of the fetus through a suction tube, used to perform abortions during the early stages of pregnancy.
- surface friction drag — the part of the drag on a body moving through a fluid that is dependent on the nature of the surface of the body
- synchrotron radiation — electromagnetic radiation emitted by charged particles as they pass through magnetic fields.
- the yellow brick road — the road to success or happiness (in the film the Wizard of Oz the yellow brick road leads to Oz)
- thermal decomposition — Thermal decomposition is the process in which a chemical species breaks down when its temperature is increased.
- third party procedure — impleader.
- third-party insurance — insurance that compensates for a loss to a party other than the insured for which the insured is liable.
- threshold wage policy — a policy whereby wages are increased in accordance with inflation
- tide-generating force — the difference between the force of gravity exerted by the moon or the sun on a particle of water in the ocean and that exerted on an equal mass of matter at the centre of the earth. The lunar tide-generating forces are about 2.2 times greater than are the solar ones
- to kill a mockingbird — a novel (1960) by Harper Lee.
- to play second fiddle — If you play second fiddle to someone, your position is less important than theirs in something that you are doing together.
- trades union congress — The Trades Union Congress in Britain is the same as the TUC.
- transactinide element — any element having an atomic number higher than 103, the last of the actinide series. These superheavy, radioactive elements are extremely short-lived, and can only be created in the laboratory.
- trichloroacetaldehyde — chloral (def 1).
- turn state's evidence — If someone who is accused of a crime turns state's evidence, they agree to give evidence in a law court against another person such as a former accomplice, usually in exchange for a reduced sentence for themselves.
- undesirable discharge — a discharge under other than honorable conditions of a person from military service by administrative action.
- university of iceland — (body, education) The Home of Fjolnir.
- vertically challenged — short in stature.
- virtual device driver — (operating system) (VxD) A device driver under Windows 3.x/Windows 95 running as part of the kernel and thus having access to the memory of the kernel and all running processes as well as raw access to the hardware. VxD's usually have the filename extension .386 under Windows 3.x and .vxd under Windows 95. VxD's written for Windows 3.x can be used under Windows 95 but not vice versa.
- white-crowned sparrow — a North American sparrow, Zonotrichia leucophrys, having black and white stripes on the head.
- white-knuckle paddler — an inexpert and timid canoeist.
- wholesale price index — an indicator of price changes in the wholesale market
- word association test — a technique for determining a subject's associative pattern by providing a verbal stimulus to which a verbal response is required.
- word-association test — a psychological test in which the person being tested responds to a given word with the first word (or the first word in a specified category, such as an antonym) brought to mind