hornbeam UK /ˈhɔːnbiːm/US /ˈhoɹnˌbim/ noun6 •A tree of the genus Carpinus, having smooth grey bark and a ridged trunk, the wood being white and very hard, found in temperate regions of the Northern Hemisphere.The Horn-beam, in Latine the Carpinus, is planted of Sets; though it may likevvise be raised from the Seeds, […] Thus it vvill advance to a considerable Tree. — 1664 •Especially, the American hornbeam (Carpinus caroliniana), which is common along the banks of streams in the United States. •Especially, the common hornbeam or European hornbeam (Carpinus betulus). •The wood of these trees or one species of them; (countable) a sample of such wood. •Synonym of beam (“the principal stem of the antler of a deer, which branches grow out from”). •(no longer used) A beam or ray of light emanating from the head of a deity like a horn. formshornbeams