Definify.com
Webster 1913 Edition
Bitters
Bit′ters
,Noun.
 pl.
 A liquor, generally spirituous in which a bitter herb, leaf, or root is steeped. 
Webster 1828 Edition
Bitters
BIT'TERS
,Noun.
  Definition 2025
bitters
bitters
English
Noun
bitters (plural bitters)
- A liquid used in mixed drinks or as a tonic into which bitter herbs have been steeped (it can also be found in powdered form for adding to mixed drinks).