The coconut tree (Cocos nucifera) is a member of the family Arecaceae (palm family) and the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which, botanically, is a drupe, not a nut. The spelling cocoanut is an archaic form of the word. The term is derived from the 16th-century Portuguese and Spanish word coco meaning “head” or “skull”, from the three indentations on the coconut shell that resemble facial features. (source)