• (written as Castor)
    Fainter of the two bright stars of the constellation Gemini, the twins, the other being Pollux. Formally called Alpha Geminorum, despite the custom that Alpha is usually the brightest star in a constellation, Castor in fact consists of six stars. A telescope resolves three stars, Castor A, B and C, and spectroscopic examination shows that each in turn is double.

Cars & Driving

  • noun an inclination or angle from the vertical of the kingpin or steering axis on the ground between the extended vertical axis through the wheel centre and the point where the extended steering axis would meet the ground.
  • noun the distance on the ground when viewed from the side, between the point of contact of the tyre (which is also the extended vertical axis through the wheel centre) and the point where a line through the inclined kingpin (or the extended steering axis) would meet the ground.

Real Estate

  • noun a small wheel on a mount that allows it to turn in all directions, attached under the corners of heavy furniture and other objects to make them easier to move

Origin & History of “castor”

there are two distinct words castor in English. The older originally meant ‘beaver’ (14th c.), and was early used with reference to a bitter pungent substance secreted by glands near the beaver’s anus, employed in medicine and perfumery. The term castor oil (18th c.) probably comes from the use of this oil, derived from the seed of a tropical plant, as a substitute for castor in medicine. The more recent castor (17th c.) is simply a derivative of the verb cast; it was originally (and still often is) spelled caster. Its use for sprinkling or ‘throwing’ sugar is obvious (the term castor sugar dates back to the mid 19th century), but its application to a ‘small swivelling wheel’ is less immediately clear: it comes from a now obsolete sense of the verb, mainly nautical, ‘veer, turn’: ‘Prepare for casting to port’, George Nares, Seamanship 1882.