Yours, Etc.: Origins and Uses of 8 Sign-Offs
1733, "fine coffee," from Mocha, Red Sea port of Yemen, from which coffee was exported. Meaning "mixture of coffee and chocolate" first recorded 1849. As a shade of dark brown, it is attested from 1895.
town, southwestern Yemen, on the Red Sea and the Tihamah coastal plain. Yemen's most renowned historic port, it lies at the head of a shallow bay between two headlands, with an unprotected anchorage 1.5 miles (2.5 km) offshore. It was long famous as Arabia's chief coffee-exporting centre; the term mocha and variations of the word have entered European languages as a synonym for the high-quality coffee of the species Coffea arabica, still grown in the Yemen Highlands and formerly exported through the town.