Aci'dity. n.s. [from acid.] The quality of being acid; an acid taste; sharpness; sourness.
Fishes, by the help of a dissolvent liquor, corrode and reduce their meats, skin, bones, and all, into a chylus or cremor; and yet this liquor manifests nothing of acidity to the taste. Ray on the Creation.
When the taste of the mouth is bitter, it is a sign of a redundance of a bilious alkali, and demands a quite different diet from the case of acidity or sourness. Arbuthnot on Aliments.