hartshorn /ˈhɑːtshɔːn/noun 2verb 1forms 3 noun2 •The antler of a hart, once used as a source of ammonia. •(old-fashioned) An aqueous solution of ammonia; smelling salts.Sophia, who had tottered along with much difficulty, sunk down in her chair; but by the assistance of hartshorn and water, she was prevented from fainting away... — 1749 verb1 •To revive with hartshorn smelling salts.Accordingly, after a vast amount of moaning and crying up-stairs, and much damping of foreheads, and vinegaring of temples, and hartshorning of noses, and so forth […] — 1841 formshartshorned · hartshorning · hartshorns