Definitions
1.nounThat part of a molecule attached to some core structure; a radical.
2.nounAny of the variable parts of amino acids that extend from the peptide backbone in proteins; they are referred to as R-groups, which branch off the backbone at the alpha carbon (Cα).
3.noun(audio) Auxiliary audio input fed to a synthesizer etc. and used to selectively trigger an effect.
4.verb(audio) To use auxiliary audio input in that manner.