coco de mer

 
Pronunciation: /ˌkəʊkəʊdəˈmɛː/

noun

  • a tall palm tree native to the Seychelles. Also called double coconut.
    • Lodoicea maldivica, family Palmae
  • the immense nut of the coco de mer tree, which is encased in a hard woody shell and is the largest known seed.

Origin:

early 19th century: from French coco-de-mer, literally 'coco from the sea' (because the tree was first known from nuts found floating in the sea)