sea coconut noun 1.alsosea coco a.: a lofty fan palm (Lodoicea seychellarum) of the Seychelle islands having leaves that are used for thatching b.: the fruit of the sea coconut which often weighs 50 pounds and in which are 3 or 4 bilobed nuts with a smooth rind — called also double coconut 2.: the fruit of the bussu