Ostrya is a genus of eight to 10 small deciduous trees belonging to the birch family Betulaceae. Its common name is hophornbeam in American English and hop-hornbeam in British English. It may also be called ironwood, a name shared with a number of other plants. The wood is very hard and heavy; the name Ostrya is derived from the Greek word ostrua, "bone-like", referring to the very hard wood. Regarded as a weed tree by some foresters, this hard and stable wood was historically used to fashion plane soles.