a tall, stout, fan palm, Lodoicea maldivica, of the Seychelles Islands, having nuts that are the largest seeds of any plant, often weighing 50 lb. (22.6 kg): populations are declining.
co·co-de-mer (kō'kō-də-mâr') n.
In both senses also called double coconut.
A fan-leaved palm (Lodoicea maldivica) native to the Seychelles, bearing the largest seed of all plants, which is enclosed in a hard shell resembling a pair of coconuts joined in the middle.