arsenic

1 of 2

noun

ar·se·nic

ˈärs-nik,

ˈär-sə-

: a solid chemical element that is used especially in wood preservatives, alloys, and semiconductors and is extremely toxic in both pure and combined forms see Chemical Elements Table

: a poisonous trioxide As₂O₃ or As₄O₆ of arsenic used especially as an insecticide or weed killer

called also arsenic trioxide

arsenic

2 of 2

adjective

ar·sen·ic är-ˈse-nik

: of, relating to, or containing arsenic especially with a valence of five

Examples of arsenic in a Sentence

Recent Examples on the Web

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Noun

Researchers warned that a failure could release waste containing toxic substances, including arsenic and mercury, potentially affecting Indigenous communities more than 40 kilometers (25 miles) downstream. — ABC News, 21 Oct. 2026 This low-temperature, low-pressure hydrometallurgical method removes arsenic cleanly and operates without fossil fuels or poisonous gas emissions. — Mrigakshi Dixit, Interesting Engineering, 19 Oct. 2026

Adjective

All the same, prosecutors requested an expert report on arsenic poisoning, which caused further delay. — D. T. Max, New Yorker, 26 Oct. 2026 During seven trial campaigns totaling 3,000 hours, researchers at the Brisbane facility tested raw concentrate with arsenic levels as high as 7 percent. — Mrigakshi Dixit, Interesting Engineering, 19 Oct. 2026 See All Example Sentences for arsenic

Word History

Etymology

Noun

Middle English arsenek, arsenic "any of various compounds of arsenic, as yellow orpiment (arsenic trisulfide)," borrowed from Anglo-French & Latin; Anglo-French arsenik, arsneke, borrowed from Latin arrhenicum, arsenicon, borrowed from Greek arsenikón, arrhenikón, probably borrowed from Aramaic zarnīḵ "arsenic" or a cognate Semitic word, borrowed from an unattested form in a Middle Iranian language (whence Persian zarnī, zarnīk "orpiment, arsenic"), a derivative of the word for "gold" (as Manichaean Parthian zrn /zarn/ "gold," zrnyn /zarnēn/ "golden"), alluding to the yellow color of orpiment

Note: The Greek word is assumed to have been reshaped by folk-etymological association with arsenikós, arrhenikós "male, masculine." Aramaic zarnīḵ is attested in a papyrus text (an order to repair a boat) dated January, 411 b.c., found in elephantine, Egypt (see A. Cowley, Aramaic Papyri of the Fifth Century B.C., Oxford, 1923, pp. 88-97; B. Porten, The Elephantine Papyri in English: Three Millennia of Cross-Cultural Continuity and Change, Brill, 1996, pp. 115-22); the word is also attested in Syriac a number of centuries later. The Manichaean Parthian forms are from D. Durkin-Meisterernst, Dictionary of Manichaean Texts, vol. III, Part 1, Dictionary of Manichaean Middle Persian and Parthian, Brepols, 2004. Parthian zrn and zrnyn are continuations of an Old Iranian etymon represented by Avestan zarańiia- "gold"—see note at gold entry 1.

Adjective

from attributive or compound use of arsenic entry 1

First Known Use

Noun

1747, in the meaning defined at sense 1

Adjective

1798, in the meaning defined above

Time Traveler

The first known use of arsenic was in 1747

See more words from the same year

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arsenian

arsenic

arsenical

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Cite this Entry

Style

“Arsenic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/arsenic. Accessed 27 Oct. 2026.

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Kids Definition

arsenic

noun

ar·se·nic

ˈärs-nik,

-ᵊn-ik

: a solid poisonous element that is commonly metallic steel-gray and brittle see element

: a white or transparent extremely poisonous oxide of arsenic used especially in insecticides

Medical Definition

arsenic

1 of 2 noun

ar·se·nic ˈärs-nik, -ᵊn-ik

: a trivalent and pentavalent solid poisonous element that is commonly metallic steel-gray, crystalline, and brittle

—symbol As see Chemical Elements Table

: arsenic trioxide

arsenic

2 of 2 adjective

ar·sen·ic är-ˈsen-ik

: of, relating to, or containing arsenic especially with a valence of five

arsenic

noun

adjective

Examples of arsenic in a Sentence

Word History

Browse Nearby Words

Cite this Entry

Kids Definition

Medical Definition

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