gum ammoniac
noun
1.
a brownish-yellow gum resin, having an acrid taste, occurring in tearlike fragments from a plant,
Dorema ammoniacum,
of western Asia: used in porcelain ceramics and in medicine as an expectorant and counterirritant.
Also called
ammoniac
,
ammoniacum
.
Origin
1350-1400;
Middle English
British Dictionary definitions for
gum ammoniac
gum ammoniac
noun
1.
another name for
ammoniac
2