Definitions of baleen

1. a horny material from the upper jaws of certain whales; used as the ribs of fans or as stays in corsets

2. Plates or blades of whalebone, from two to twelve feet long, and sometimes a foot wide, which in certain whales ( Balaenoidea) are attached side by side along the upper jaw, and form a fringelike sieve by which the food is retained in the mouth.

3. Whalebone.

4. The horny plates attached to the upper jaw of true whales; whalebone.