car ‧ at /ˈkærət/ BrE AmE noun [countable] British English
[ Date: 1400-1500 ; Language: French ; Origin: Arabic qirat 'bean pod, small weight' , from Greek keration 'carob bean, small weight' ]
1 . ( also karat American English ) a unit for measuring how pure gold is
9/18/22/24 carat gold
a 22 carat gold chain
Pure gold is 24 carats.
2 . a unit for measuring the weight of jewels, equal to 200 ↑ milligram s :
the Orloff diamond, a stone of 194.5 carats