is a recognized element of the English system of measurements -- though it is usually called an ounce (Latin usually triumphs over the good, old Anglo-Saxon terms!)
one handful = 2 mouthfuls = 2 tablespoons
one mouthful = 4 drams
one dram = 60 minims
A minim is essentially one liquid drop.
By the way, a "pinch" = 5 minims, and a "dash" = 10 minims.
Not universally recognized, of course! · ·