'Intramolecular' definitions:

Definition of 'intramolecular'

adjective

Within the molecule; occurring by a reaction between different parts of the same molecule

From: GCIDE

Intramolecular \In`tra*mo*lec"u*lar\, a.
1. (Chem. & Physics) Between molecules; situated, or acting, between the molecules of bodies. [Obs.] [1913 Webster]
2. Being or occurring within a single molecule; as, intramolecular hydrogen bonds. [PJC]