intra-

in organic reaction mechanisms
https://doi.org/10.1351/goldbook.I03128
The prefix for an @E02035@ or some part thereof indicating that the bond(s) undergoing primitive changes form part of a ring in the @T06468@ of the @E02035@. This prefix is used for nonpericyclic processes only and is replaced by 'cyclo' for pericyclic processes.
Source:
PAC, 1989, 61, 23. (System for symbolic representation of reaction mechanisms (Recommendations 1988)) on page 34 [Terms] [Paper]