Full Definition of FACET. 1. : a small plane surface (as on a cut gem) â see brilliant illustration. 2. : any of the definable aspects that make up a subject (as of contemplation) or an object (as of consideration). 3. : the external corneal surface of an ommatidium.
Definition of cyanide. 1  1 : a compound of cyanogen with a more electropositive element or group: such asa : potassium cyanideb : sodium cyanide. 2  2 : cyanogen 1.
noun, Chemistry. 1. an element that is a dark-reddish, fuming, toxic liquid and a member of the halogen family: obtained from natural brines and ocean water, and used chiefly in the manufacture of gasoline antiknock compounds, pharmaceuticals, and dyes.