[ noun ahr-suh-nik, ahrs-nik; adjective ahr-sen-ik ]
/ noun ˈɑr sə nɪk, ˈɑrs nɪk; adjective ɑrˈsɛn ɪk /


a grayish-white element having a metallic luster, vaporizing when heated, and forming poisonous compounds. Symbol: As; atomic weight: 74.92; atomic number: 33.
a mineral, the native element, occurring in white or gray masses.

adjective ar·sen·ic [ahr-sen-ik] /ɑrˈsɛn ɪk/

of or containing arsenic, especially in the pentavalent state.

Origin of arsenic

1350–1400; Middle English arsenicum < Latin < Greek arsenikón orpiment, noun use of neuter of arsenikós virile (ársēn male, strong + -ikos -ic), probably alteration of Semitic word (perhaps < *arznig, metathetic variant of Syriac zarnig) by folk etymology
Related formsnon·ar·sen·ic, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for arsenic

British Dictionary definitions for arsenic


noun (ˈɑːsnɪk)

a toxic metalloid element, existing in several allotropic forms, that occurs principally in realgar and orpiment and as the free element. It is used in transistors, lead-based alloys, and high-temperature brasses. Symbol: As; atomic no: 33; atomic wt: 74.92159; valency: –3, 0, +3, or +5; relative density: 5.73 (grey); melting pt: 817°C at a pressure of 3MN/m² (grey); sublimes at 613°C (grey)
a nontechnical name for arsenic trioxide

adjective (ɑːˈsɛnɪk)

of or containing arsenic, esp in the pentavalent state

Word Origin for arsenic

C14: from Latin arsenicum, from Greek arsenikon yellow orpiment, from Syriac zarnīg (influenced in form by Greek arsenikos virile)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for arsenic



late 14c., from Old French arsenic, from Latin arsenicum, from late Greek arsenikon "arsenic" (Dioscorides; Aristotle has it as sandarake), adapted from Syriac (al) zarniqa "arsenic," from Middle Persian zarnik "gold-colored" (arsenic trisulphide has a lemon-yellow color), from Old Iranian *zarna- "golden," from PIE root *ghel- "to shine" (see Chloe).

The form of the Greek word is folk etymology, literally "masculine," from arsen "male, strong, virile" (cf. arseno-koites "lying with men" in New Testament) supposedly in reference to the powerful properties of the substance. The mineral (as opposed to the element) is properly orpiment, from Latin auri pigmentum, so called because it was used to make golden dyes.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for arsenic


[ ärsə-nĭk ]

n. Symbol As

A poisonous metallic element, compounds of which are used as antamebics. Atomic number 33.


Of or containing arsenic, especially with valence 5.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for arsenic


[ ärsə-nĭk ]


A metalloid element most commonly occurring as a gray crystal, but also found as a yellow crystal and in other forms. Arsenic and its compounds are highly poisonous and are used to make insecticides, weed killers, and various alloys. Atomic number 33; atomic weight 74.922; valence 3, 5. Gray arsenic melts at 817°C (at 28 atm pressure), sublimes at 613°C, and has a specific gravity of 5.73. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.