Definition

1. Noun:
   • A type of small wheel: A castor is a small wheel, typically one that can swivel, attached to the bottom of furniture or equipment to make it easy to move.
   • A beaver: Castor is the genus name for beavers, the large, semiaquatic rodents known for building dams and lodges.
   • A container with holes: A castor is a small container, often with a perforated top, used for sprinkling substances like sugar or pepper.
   • A star: Castor is the name of a bright star in the constellation Gemini, traditionally part of a multiple-star system.

Examples

• Noun (Wheel):

  • The office chair has smooth-rolling castors.
  • We added castors to the heavy cabinet so we could move it easily.

• Noun (Animal):

  • The scientific name for the North American beaver is Castor canadensis.
  • The fur trade once heavily relied on the castor.

• Noun (Container):

  • She picked up the sugar castor to dust the cake.
  • The table was set with silver salt and pepper castors.

• Noun (Star):

  • Castor and Pollux are the two brightest stars in the constellation Gemini.
  • Astronomers have discovered that Castor is actually a system of six stars.

Advanced Usage

• "Castor oil": A thick vegetable oil obtained from the seeds of the castor oil plant (), used historically as a laxative and in various industrial applications.
  • Castor oil was a common home remedy in the past.

Variants and Related Words

• Caster: An alternative, and often preferred, spelling for the wheel and the shaker/sprinkler meanings. (e.g., , ).
• Castoreum: A secretion from the castor (beaver) used in perfumery and traditional medicine.

Synonyms

• For the wheel: Roller, wheel, swivel.
• For the animal: Beaver.
• For the container: Shaker, sprinkler, dredger.
• For the star: Alpha Geminorum (astronomical designation).

Noun

1. type genus of the Castoridae: beavers
2. a hat made with the fur of a beaver (or similar material)
3. a pivoting roller attached to the bottom of furniture or trucks or portable machines to make them movable
4. a shaker with a perforated top for sprinkling powdered sugar
5. a multiple star with 6 components; second brightest in Gemini; close to Pollux