coco-de-mer

enUK

co·co-de-mer

C0448500 (kō′kō-də-mâr′)n.1. A fan-leaved palm (Lodoicea maldivica) native to the Seychelles, having an extremely large seed enclosed in a hard shell resembling a pair of coconuts.2. The seed of this plant. In both senses also called double coconut.
[French : coco, coconut + de, of + mer, sea.]