Definition of "hartshorn" [harts•horn]

• The antler of a hart, formerly used as a source of ammonia and in smelling salts. (noun)
• Ammonium carbonate. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "By the simple action of water and heat, the gelatine is separated; but in order to procure the ammonia, or what is commonly called hartshorn, the bones must be distilled, by which means the gelatine is decomposed, and hydrogen and nitrogen combined in the form of ammonia."
• "For leavening, purists prefer a pinch of hartshorn aka baker's ammonia, which is traditional in Scandinavian baking and thought to produce a tender, fluffier crumb—but conventional baking powder more than suffices."
• "The first is a body recognized by its extremely pungent smell, and commonly known as hartshorn, and is formed by the union of two elements -- nitrogen and hydrogen."