carat: [16] The carat gets its name from the use of carob beans as standard weights for measuring the heaviness of small quantities. The Greek name for the elongated seed pod of the carob tree was kerátion, a derivative of kéras ‘horn’ (related to English horn). This passed into Arabic as qīrāt, where it became formalized in a system of weights and measures as ‘four grains’. It passed into English via Italian carato and French carat. => horn
carat (n.)
also karat, mid-15c., from Middle French carat "measure of the fineness of gold" (14c.), from Italian carato or Medieval Latin carratus, both from Arabic qirat "fruit of the carob tree," also "weight of 4 grains," from Greek keration "carob seed," also the name of a small weight of measure (one-third obol), literally "little horn" diminutive of keras "horn" (see kerato-).
Carob beans were a standard for weighing small quantities. As a measure of diamond weight, from 1570s in English. The Greek measure was the equivalent of the Roman siliqua, which was one-twentyfourth of a golden solidus of Constantine; hence karat took on a sense of "a proportion of one twentyfourth" and became a measure of gold purity (1550s). Eighteen carat gold is eighteen parts gold, six parts alloy. It is unlikely that the classical carat ever was a measure of weight for gold.
例文
1. an 18- carat gold ring
18からの金の指輪
2.She has a four- carat stone in herring.
彼女の指輪には4カラットの宝石がはめ込まれている。
3.Can you believe that he bought her a 5.3- carat diamond ring？
あなたは知っていますか、彼は彼女に5.3カラットのダイヤモンドの指輪を買ったのですか？
4.One sign of Mastitis mastitis is carat cracked skin on the tisteats.
乳がんの1つは、**皮膚が裂け、同時に乳腺が発熱し、痛みが大きくなることです。
5.This diamond,may process is 150 carat fine diamonds.