Definition of: assay

(ə·sā′, as′ā) noun
1. The chemical analysis or testing of an alloy or ore, to ascertain the ingredients and their proportions.
2. The substance to be so examined.
3. The result of such a test.
4. Any examination or testing.
5. Obs. Attempt; trial.
—v.t. (ə·sā′)
1. To subject to chemical analysis; make an assay of.
2. To prove; test.
3. Obs. To attempt.
—v.i.
4. To show by analysis a certain value or proportion, as of a precious metal: to assay low in platinum. [<OF assai, var. of essai trial <L exagium a weighing <exigere prove <ex- out + agere drive, do. Doublet of ESSAY.]
—as·say′er noun