What does "hartshorn" mean?

Hartshorn: Spirits of hartshorn (see below); volatile salts. Hartshorn plantain (Bot.), an annual species of plantain (Plantago Coronopus); -- called also duck's-horn. Booth. -- Hartshorn shavings, originally taken from the horns of harts, are now obtained chiefly by planing down the bones of calves. They afford a kind of jelly. Hebert. -- Salt of hartshorn (Chem.), an impure solid carbonate of ammonia, obtained by the destructive distillation of hartshorn, or any kind of bone; volatile salts. Brande & C.-- Spirits of hartshorn (Chem.), a solution of ammonia in water; -- so called because formerly obtained from hartshorn shavings by destructive distillation. Similar ammoniacal solutions from other sources have received the same name. HART-TONGUE; HART'S-TONGUE Hart"-tongue`, Hart's"-tongue`, n. (Bot.) (a) A common British fern (Scolopendrium vulgare), rare in America. (b) A West Indian fern, the Polypodium Phyllitidis of Linnæus. It is also found in Florida.