The hophornbeam is closely related to the hornbeams (Carpinus spp.) and both represent species of small deciduous trees. They have alternate leaves that are toothed similar to the birches. In the spring, they produce catkins and carry their seeds in a small nut enclosed in a bladder like involucre.

Hophornbeam wood is very dense and heavy, thus the other common name, Ironwood. The Greek word, Ostrya, means "bone like."