as·say / ˈaˌsā; aˈsā/ • n. the testing of a metal or ore to determine its ingredients and quality: submission of plate for assay. ∎  a procedure for measuring the biochemical or immunological activity of a sample: each assay was performed in duplicate.• v. [tr.] 1. determine the content or quality of (a metal or ore). ∎  determine the biochemical or immunological activity of (a sample): cell contents were assayed for enzyme activity. ∎  examine (something) in order to assess its nature: stepping inside, I quickly assayed the clientele.2. archaic attempt: I assayed a little joke of mine on him.DERIVATIVES: as·say·er n.

assay the testing of a metal or ore to determine its ingredients and quality. The word is recorded from Middle English, in the general sense ‘testing, or a test of, the merit of someone or something’, and comes ultimately from Old French essai ‘trial’.

In the UK, the assay office is an institution authorized to award hallmarks to articles made from precious metals. There are currently four in Britain, at London, Birmingham, Sheffield, and Edinburgh.

assay Test to determine the amount of a metal present in a sample of material such as ores and alloys. The term is normally reserved for finding the proportion of gold, silver or platinum present. See also hallmark

assay trial (gen. and spec., now only of metals). XIV. — OF. assai, var. of essai ESSAY.
So assay vb. XIV. — OF. assaier.

assay The analysis of minerals and mine products to determine the concentrations of their components.