cyanide
1. cy.a.nide \'si--*-.ni-d, -n*d\ n [ISV] : a compound of cyanogen usu. with a more electropositive element or radic al 2. cy.a.nide \-.ni-d\ vt : to treat with a cyanide; specif : to treat (iron or steel) with molten cyanide to produce a hard surface