One of a group of organic chemical compounds of general formula RC≡N. A nitrile is named from the acid to which it can be hydrolyzed by adding the suffix -onitrile to the acid stem, for example, acetonitrile from acetic acid. An alternative system names the group attached to CN, thus CH₃CN is also named methyl cyanide. In more complex structures the CN group is named as a substituent, cyano.