Definition of "Assay" :
noun: 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.
noun: an appraisal of the state of affairs
"They made an assay of the contents."
noun: a written report of the results of an analysis of the composition of some substance
noun: a substance that is undergoing an analysis of its components
verb: analyze (chemical substances)
verb: make an effort or attempt