Any of several small marine oysters of the genus Pinctada, especially P. fucata, cultivated in Japan, China, and elsewhere for the production of cultured pearls. Also: a pearl so produced, typically round, white, and lustrous. Usually attributive as "Akoya oyster", "Akoya pearl", etc.
Until the second half of the 20th century apparently only in translations of, after, or with allusion to E. Kämpfer Hist. Japan.
Early 18th century; earliest use found in John Scheuchzer (1702–1729), physician and naturalist. From German Akoja and (in later use) its etymon Japanese akoya, short for akoya-dama akoya pearl from Akoya, the former name of Honda, a coastal town in the Aichi prefecture, Japan (known for the abundance in pearl oysters in its bay) + -dama, combining form of tama ball, gem, bead.