carat vs karat

carat and karat both are nouns.

Word	Noun	Adjective	Verb	Adverb
carat	Yes	No	No	No
karat	Yes	No	No	No

As nouns, carat and karat are synonyms defined as:

carat and karat: the unit of measurement for the proportion of gold in an alloy; 18-karat gold is 75% gold; 24-karat gold is pure gold

Other synonyms of carat include kt.

carat (noun)	karat (noun)
a unit of weight for precious stones = 200 mg	the unit of measurement for the proportion of gold in an alloy; 18-karat gold is 75% gold; 24-karat gold is pure gold
the unit of measurement for the proportion of gold in an alloy; 18-karat gold is 75% gold; 24-karat gold is pure gold