assay

American  

[a-sey, as-ey, a-sey] / æˈseɪ, ˈæs eɪ, æˈseɪ /

verb (used with object)

1. to examine or analyze.

   to assay a situation; to assay an event.

2. Metallurgy. to analyze (an ore, alloy, etc.) in order to determine the quantity of gold, silver, or other metal in it.

3. Pharmacology. to subject (a drug) to an analysis for the determination of its potency or composition.

4. to judge the quality of; assess; evaluate.

   to assay someone's efforts.

5. to try or test; put to trial.

   to assay one's strength; to assay one's debating abilities.

6. to attempt; try; essay.

   to assay a dance step.

---

verb (used without object)

1. to contain, as shown by analysis, a certain proportion of usually precious metal.

noun

1. Metallurgy. determination of the amount of metal, especially gold or silver, in an ore, alloy, etc.

2. a substance undergoing analysis or trial.

3. a detailed report of the findings in assaying a substance.

4. Archaic. examination; trial; attempt; essay.

assay British  

verb

1. to subject (a substance, such as silver or gold) to chemical analysis, as in the determination of the amount of impurity

2. (tr) to attempt (something or to do something)

3. (tr; may take a clause as object) to test, analyse, or evaluate

   to assay the significance of early childhood experience

---

noun

1. 1. an analysis, esp a determination of the amount of metal in an ore or the amounts of impurities in a precious metal

   2. ( as modifier )

      an assay office

2. a substance undergoing an analysis

3. a written report on the results of an analysis

4. a test

5. archaic an attempt

assay Scientific  

/ ăs′ā,ə-sā′ /

1. A quantitative determination of the amount of a given substance in a particular sample. Assays are regularly used to determine the purity of precious metals. They can be performed by wet methods or dry methods. In the wet method, the sample is dissolved in a reagent, like an acid, until the purified metal is separated out. In the dry method, the sample is mixed with a flux (a substance such as borax or silica that helps lower the melting temperature) and then the sample is heated to the point where impurities in the metal fuse with the flux, leaving the purified metal as a residue.

2. A bioassay.

---

Other Word Forms

• assayable adjective
• assayer noun
• unassayed adjective
• unassaying adjective

Etymology

Origin of assay

1250–1300; Middle English < Middle French; variant of essay

Explanation

An assay is a breakdown of a material, examining the individual parts that make up the whole. When you assay a situation, you look at all the elements that created the problem in order to come up with a solution. The word assay comes from the French word essai, which means "trial," an appropriate sense for a word that means to examine for analysis. As a noun, assay means a test or appraisal to determine the components of a substance or object. As a verb, it refers to the act of analyzing, or of conducting that test. It is usually used in chemistry-related fields like metallurgy and pharmaceuticals, but you can also assay a poem.

Example Sentences

The liver fibrosis assay described in the study remains a prototype and has not yet been introduced as a clinical test.

From Science Daily • Mar. 6, 2026

Dash, whose team includes former software engineers from Moderna, automates common laboratory tests such as Elisa, or enzyme-linked immunosorbent assay, which is used for tasks such as evaluating a drug’s safety and efficacy.

From The Wall Street Journal • Jul. 23, 2025

We set up an inhibition assay in test tubes.

From Salon • Dec. 16, 2024

The new assay aligns with ongoing efforts by state and federal agencies, which have invested more than $10 million from 2004 to 2021 to manage the Burmese pythons alone.

From Science Daily • Nov. 22, 2024

How can one assay the total impact of the unprecedented calamity that gave rise to the world we live in?

From "1491" by Charles C. Mann