assay

1 of 2

verb

as·​say a-ˈsā  ˈa-ˌsā 

assayed; assaying; assays

transitive verb

1

a

: to analyze (something, such as an ore) for one or more specific components

assayed the gold to determine its purity

b

: to judge the worth of : estimate

assay the results of the new changes

2

: try, attempt

Again Israel assayed to reply, but could not.

—Herman Melville

intransitive verb

: to prove up in an assay

assayer noun

assay

2 of 2

noun

as·​say ˈa-ˌsā  a-ˈsā 

1

: examination and determination as to characteristics (such as weight, measure, or quality)

2

: analysis (as of an ore or drug) to determine the presence, absence, or quantity of one or more components

also : a test used in this analysis

3

: a substance to be assayed

also : the tabulated result of assaying

4

archaic : trial, attempt

Did you know?

Usage experts warn against confusing the verbs assay and essay. Some confusion shouldn’t be surprising; not only do the two somewhat uncommon words look and sound alike, they also come from the same root, the Middle French word essai, meaning "test" or "effort." (Essai, in turn, comes from the Late Latin word exagium, meaning "act of weighing.") At one time, the two terms were synonyms, sharing the meaning "try" or "attempt," but they are now typically differentiated, with essay meaning "to try or attempt" (as in "a comedic actor essaying her first dramatic role") and assay meaning "to test or evaluate" (as in "blood assayed to detect the presence of the antibody"). Of course, essay is more common as a noun referring to a short analytic or personal literary composition, but that’s another essay.

Synonyms

Verb

• analyze
• anatomize
• break down
• cut
• deconstruct
• dissect

Noun

• analysis
• anatomizing
• anatomy
• breakdown
• deconstruction
• dissection

Examples of assay in a Sentence

Verb

They assayed the gold to determine its purity.

the company assayed a sample of the rock to see if it contained gold in quantities worth mining

Noun

a metallurgist did an assay on the metal and determined it contained nickel

the poem about a frustrated man's last assay at greatness

Recent Examples on the Web

Verb

The plan, which has a capital cost estimate of US$3.3 billion, is to mine ore at Mt Bevan, located in central Western Australia, upgrading it from a run-of-mine 33.52% iron into a concentrated product assaying more than 70% iron. —Tim Treadgold, Forbes, 21 Oct. 2024

The 950-pound rover could navigate treacherous lunar terrain to reach a site of interest, assay the soil’s ice content with three-foot-deep drilling and then move on to another location to do it all again. —Michael Greshko, Scientific American, 24 July 2024

Noun

Impressive copper rich outcrops (formed from blue azurite, a copper oxide) have been identified with many assay results in the laboratory, including channel sampling up to 192 m long (Picture 1). —Sacramento Bee, 2 July 2024

For example, a person infected with West Nile virus may also test positive by IgM assays for St. Louis encephalitis or dengue. —Matthew Binnicker, Forbes, 7 Sep. 2024

Word History

Etymology

Noun and Verb

Middle English, from Anglo-French assai, essai — more at essay entry 1

First Known Use

Verb

14th century, in the meaning defined at transitive sense 2

Noun

14th century, in the meaning defined at sense 4

Phrases Containing assay

• enzyme-linked immunosorbent assay

Podcast

Get Word of the Day delivered to your inbox!

Kids Definition

assay

1 of 2 noun

as·​say ˈas-ˌā 

a-ˈsā

: examination (as of an ore, metal, or drug) for the purpose of determining the presence, absence, or amount of one or more substances

assay

2 of 2 verb

as·​say a-ˈsā 

ˈas-ˌā

1

: try entry 1 sense 4, attempt

2

: to analyze (as an ore) for one or more valuable substances

assayer noun

Medical Definition

assay

1 of 2 noun

as·​say ˈas-ˌā  a-ˈsā 

1

: examination and determination as to characteristics (as weight, measure, or quality)

2

: analysis (as of a drug) to determine the presence, absence, or quantity of one or more components compare bioassay

3

: a substance to be assayed

also : the tabulated result of assaying

assay

2 of 2 transitive verb

as·​say a-ˈsā  ˈas-ˌā 

: to analyze (an impure substance or mixture) for one or more specific components

the sample was assayed for drug content