A variety of maple tree of eastern North America, Acer nigrum, closely related to the sugar maple, but with a darker bark and three-lobed leaves.

The thornback guitarfish (Platyrhinoidis triseriata), a species of ray in the north-eastern Pacific Ocean. / The thornback ray or thornback skate (Raja clavata), a species of ray in the Atlantic Oc...

plural of airling

Inflammation of a periosteum