Definition of assay in English:

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Pronunciation: /ˈaˌsā/
Pronunciation: /aˈsā/


1The testing of a metal or ore to determine its ingredients and quality: submission of plate for assay
evaluation, assessment, appraisal, analysis, examination, test/tests, testing, inspection, scrutiny
1.1A procedure for measuring the biochemical or immunological activity of a sample: each assay was performed in duplicate the results of sequential assays of serum were analyzed immunofluorescence assay
More example sentences
  • None of the antigenic assays can measure the functional activity of the protein.
  • All cholesterol assays measure the total cell cholesterol, so it is not possible to distinguish between plasma membrane cholesterol and intracellular cholesterol.
  • This warns against inadvertent overestimation due to the original sampling procedure in experimental assays.


[with object]
1Determine the content or quality of (a metal or ore).
Example sentences
  • Some of the copper ore was assayed in England leading to the formation of a London mining association made up of ten members, each promising to invest $2,000 for further prospecting on the property.
  • The bank is to set up a separate unit, SBI Gold and Precious Metals, to assay the gold and jewellery brought in as deposits.
  • Captain Lewis now planned to build a furnace for the purpose of assaying the ore.
1.1Determine the biochemical or immunological activity of (a sample): cell contents were assayed for enzyme activity
More example sentences
  • Solubilized samples were assayed for total protein content using the EZQ Protein Quantitation Kit (Molecular Probes, Eugene, OR).
  • The samples were assayed for CHH by an enzyme-linked immunosorbent assay.
  • Nitric oxide and nitrogen dioxide were chemically assayed as nitrite from sorbent tubes by using spectrophotometry.
1.2Examine (something) in order to assess its nature: stepping inside, I quickly assayed the clientele
More example sentences
  • We assay variation in a natural population to assess whether microsatellite markers can be informative for future studies in this species.
  • Transcription rates were assayed using nuclear run-on analyses as previously described.
  • On those rare occasions when he assays an argument, it's indisputable that nothing will ever rescue him from mediocrity.
evaluate, assess, appraise, analyze, examine, test, inspect, scrutinize, probe
2 archaic Attempt: I assayed a little joke of mine on him
More example sentences
  • Point made, he assays a few kicks in the air and brings it home: ‘Turn it up now!’



Pronunciation: /ˈasāər/
Example sentences
  • Specimens of the metal were sent to expert assayers for analysis.
  • This tribe was far too complex for modern assayers.
  • After studying chemistry at University College, London, and working as an assayer in Australia, he returned to University College in 1859 to study political economy, philosophy, and mathematics.


Middle English (in the general sense 'testing, or a test of, the merit of someone or something'): from Old French assai (noun), assaier (verb), variant of essai 'trial', essayer 'to try' (see essay).

  • essay from Late Middle English:

    Essay is a variant of assay (Middle English) ‘try, test’, going back to Latin exigere ‘ascertain, weigh’. In writing contexts, it referred initially to ‘a first draft’ but came to mean ‘a composition’. This use seems to have been taken from the French philosopher and essayist Montaigne (1533–92) whose Essais were first published in 1580.

Words that rhyme with assay

affray, agley, aka, allay, Angers, A-OK, appellation contrôlée, array, astray, au fait, auto-da-fé, away, aweigh, aye, bay, belay, betray, bey, Bombay, Bordet, boulevardier, bouquet, brae, bray, café au lait, Carné, cassoulet, Cathay, chassé, chevet, chez, chiné, clay, convey, Cray, crème brûlée, crudités, cuvée, cy-pres, day, decay, deejay, dégagé, distinguée, downplay, dray, Dufay, Dushanbe, eh, embay, engagé, essay, everyday, faraway, fay, fey, flay, fray, Frey, fromage frais, gainsay, Gaye, Genet, giclee, gilet, glissé, gray, grey, halfway, hay, heigh, hey, hooray, Hubei, Hué, hurray, inveigh, jay, jeunesse dorée, José, Kay, Kaye, Klee, Kray, Lae, lay, lei, Littré, Lough Neagh, lwei, Mae, maguey, Malay, Mallarmé, Mandalay, Marseilles, may, midday, midway, mislay, misplay, Monterrey, Na-Dene, nay, né, née, neigh, Ney, noway, obey, O'Dea, okay, olé, outlay, outplay, outstay, outweigh, oyez, part-way, pay, Pei, per se, pince-nez, play, portray, pray, prey, purvey, qua, Quai d'Orsay, Rae, rangé, ray, re, reflet, relevé, roman-à-clef, Santa Fé, say, sei, Shar Pei, shay, slay, sleigh, sley, spae, spay, Spey, splay, spray, stay, straightaway, straightway, strathspey, stray, Sui, survey, sway, Taipei, Tay, they, today, tokay, Torbay, Tournai, trait, tray, trey, two-way, ukiyo-e, underlay, way, waylay, Wei, weigh, wey, Whangarei, whey, yea

For editors and proofreaders

Syllabification: as·say

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