Castor

How to spell castor

6 letters · 2 syllables

How to pronounce castor

Say the part in capitals loudest.

What does castor mean?

1. nounA thick oil pressed from the seeds of the Ricinus plant, used as a purgative and as a lubricant.
2. nounA very fine white sugar used in baking, finer than granulated but coarser than icing sugar.
3. nounA small swivelling wheel fixed to the base of furniture so it can be rolled in any direction.

Castor in a sentence

• A spoonful of castor oil was once a common home remedy.

• Cream the butter with the castor sugar until the mixture turns pale.

• One castor on the office chair had snapped, so it rolled in a crooked line.

• The mechanic kept a tin of castor oil for the old engine bearings.

• The meringue needs castor sugar so it dissolves quickly into the egg whites.

• He fitted a brass castor to each leg of the heavy cabinet.

Where does castor come from?

Language of origin: Greek

This word traces back to the Greek kastor, the name for the beaver, which passed almost unchanged into Latin as castor and then into English. The animal mattered commercially because of castoreum, a strong-smelling oily secretion taken from glands near the beaver's tail and once prized in medicine and perfumery. When a purgative oil pressed from the seeds of the tropical Ricinus plant came into use, it was marketed as 'castor oil' because it was sold as a substitute for, or in the same trade as, that beaver product, and the name stuck even though no beaver is involved. The small swivelling furniture wheel is a different thread: that 'castor' (also spelled 'caster') comes from the verb 'cast', in the sense of to throw or turn, because the wheel lets a piece of furniture be rolled and steered in any direction. 'Castor sugar', the very fine British baking sugar, is named for the small perforated castor or shaker through which such sugar was sprinkled. The shared spelling masks these separate origins, which is exactly why the word is easy to slip on.

How the word is built

• castor (from Greek kastor: beaver), the modern senses extend by association from the beaver and its secretion

Words that sound like castor

They sound the same but mean different things, so the meaning decides which spelling to write.

• caster: A small swivelling wheel fixed to the leg or base of furniture so it can be rolled.