a quantitative or qualitative test of a substance (especially an ore or a drug) to determine its components; frequently used to test for the presence or concentration of infectious agents or antibodies etc.
an appraisal of the state of affairs; "they made an assay of the contents"; "a check on its dependability under stress"
a written report of the results of an analysis of the composition of some substance
a substance that is undergoing an analysis of its components