- a hart's antler
- Now Rare ammonium carbonate, used in smelling salts; sal volatile: so called because formerly obtained from deers' antlers
- The antler of a hart, formerly used as a source of ammonia and in smelling salts.
- See ammonium carbonate.
(third-person singular simple present hartshorns, present participle hartshorning, simple past and past participle hartshorned)