weight

Concise Oxford English Dictionary © 2008 Oxford University Press:
weight/weɪt/

▶noun

• 1 a body's relative mass or the quantity of matter contained by it, giving rise to a downward force; heaviness.

  ■ Physics the force exerted on the mass of a body by a gravitational field.

  ■ the quality of being heavy.

  ■ a unit or system of units used for expressing how much something weighs.

• 2 a piece of metal known to weigh a definite amount and used on scales to determine how heavy something is.

  ■ a heavy object, especially one being lifted or carried or used as a counterpoise in a mechanism.

  ■ (weights) heavy blocks or discs used in weightlifting or weight training.

• 3 the surface density of cloth, used as a measure of its quality.

• 4 ability to influence decisions or actions.

  ■ the importance attached to something.

• 5 a feeling of oppression or pressure: a weight on one's mind.

• 6 Statistics a factor associated with one of a set of numerical quantities, used to represent its importance relative to the other members of the set.

▶verb

• 1 hold (something) down by placing a heavy object on top of it.

• 2 attach importance or value to.

  ■ plan or arrange so as to give someone or something an advantage.

• 3 Statistics multiply the components of (an average) by factors to take account of their importance.

• 4 assign a handicap weight to (a horse).

• 5 treat (a fabric) with a mineral to make it seem thicker and heavier.

– phrases
be worth one's weight in gold be very useful or helpful.
throw one's weight about (or around) informal be unpleasantly self-assertive.

– origin OE (ge)wiht, of Gmc origin; form influenced by weigh1.