cubit (n.) Look up cubit at Dictionary.com
ancient unit of measure based on the forearm from elbow to fingertip, usually from 18 to 22 inches, early 14c., from Latin cubitum "the elbow," from PIE *keu(b)- "to bend." Such a measure, known by a word meaning "forearm" or the like, was known to many peoples (Greek pekhys, Hebrew ammah, English ell).