Cocoa as a food item was first introduced to Japan via Dutch-controlled Nagasaki during the Edo Period. Japanese adopted the Dutch word for "cocoa", cacao, becoming カカオ, as the word for the cocoa plant. Cocoa powder was introduced to Japan later in the mid-1800s, at which point the Japanese language adopted the English word cocoa for the powder and the beverage made from it. The Japanese katakana rendering ココア and pronunciation [ko̞ko̞a̠], pronouncing the "a" on the end separately, suggests that the word was borrowed phonetically from written text. The distinct "a" on the end might also have been a conscious decision on the part of whomever first used the word ココア in Japanese, in order to avoid confusion with the many possible homophones for words pronounced [ko̞ko̞], [ko̞ko̞ː], [ko̞ːko̞], or [ko̞ːko̞ː] (see ここ, ここう, こうこ, こうこう).
ココア (romaji kokoa)