Wordnet 3.0
NOUN (1)
1.
a pungent preparation of ammonium carbonate and perfume;
sniffed as a stimulant to relieve faintness;
The Collaborative International Dictionary of English v.0.48:
Smelling salts \Smell"ing salts\
An aromatic preparation of carbonate of ammonia and, often,
some scent, to avoid or relieve faintness, headache, or the
like.
[Webster 1913 Suppl.]
WordNet (r) 3.0 (2006):
smelling salts
n 1: a pungent preparation of ammonium carbonate and perfume;
sniffed as a stimulant to relieve faintness