The New Student's Reference Work/Horn
Horn, the name, in a general sense, applied to the hard bone-like substance growing from the heads of animals. Horns are of two kinds: one being a continuation of growth of the actual bone structure and the second being a hardening of the epidermis or skin. They may be solid or hollow; the hollow horn being but a single column, as a rule; the bony or solid horn is usually branched or pronged. The name is also applied to the nails, hoofs, claws, bills and quills of animals. Horn is manufactured into many articles of use and ornament, and has been so used from the earliest period. Thin plates of horn were once used for window-panes, lanterns and book-covers, whence the name hornbook. It is used in making handles for knives, forks, umbrellas and canes; for combs, buttons, drinking cups, snuff and other boxes. The horn in its natural form has been largely used for holding powder, many powder-horns being beautifully carved.