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.NounAuxiliary audio input fed to a synthesizer etc. and used to selectively trigger an effect.
4.NounA separate blockchain attached to a parent blockchain (mainchain) to extend its functionalities.
5.NounOn some railways, a chain fitted on both sides of a centre coupler or buffer at each end of a rail vehicle, which has a hook for connection to a corresponding chain on the next vehicle in a train.
6.VerbTo use auxiliary audio input in that manner.