What is the meaning of Carat?

A metric unit of mass equal to exactly 200 mg, chiefly used for measuring precious stones and pearls.

Any of several small units of mass used for measuring precious stones and pearls, equivalent to 189–212 mg.

A 24-point scale used to measure the purity of gold.

carat

carat (measure of purity of gold)

genitive singular/plural of cara (“friend; relative”)

genitive singular/dual/plural of cara

carat, karat

Source: wiktionary.org