Any of various salts or esters of hydrogen cyanide containing a CN group, especially the extremely poisonous compounds potassium cyanide and sodium cyanide.
To treat (a metal surface) with cyanide to produce a hard surface.
To treat (an ore) with cyanide to extract gold or silver.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.