/ ˈɑːsnɪk; NAmE ˈɑːrs-/ noun
[ U ] ( symb As ) a chemical element. Arsenic is an extremely poisonous white powder.
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WORD ORIGIN
late Middle English (denoting yellow orpiment (a mineral), arsenic sulphide): via Old French from Latin arsenicum , from Greek arsenikon yellow orpiment, identified with arsenikos male, but in fact from Arabic al-zarnīḵ the orpiment (a bright yellow mineral), based on Persian zar gold.