Definition of bitterns:
(n) :
Several bird species in the Botaurinae subfamily of the heron family Ardeidae.
(n) :
The liquor remaining after halite (common salt) has been harvested from saline water (brine).
(n) :
The saline substance added to soy milk to coagulate it as a primary step in the production of tofu.
(n) :
(archaic) A very bitter compound of quassia, cocculus indicus, etc., used by fraudulent brewers in adulterating beer.
(n) :
A town in the Shire of Mornington Peninsula, Victoria, Australia