heteroconjugation

https://doi.org/10.1351/goldbook.H02796
  1. [obsolete] Association between a base and the conjugate acid of a different base through a hydrogen bond (B' … HB+ or A'H … A−). The term has its origin in the conjugate acid–base pair and is in no way related to conjugated systems of orbitals. Heteroassociation is a more appropriate term.
  2. [obsolete] Some authors refer to conjugated systems containing a heteroatom, e.g. pyridine, as 'heteroconjugated systems'. This usage is discouraged since it inappropriately suggests an analogy to homoconjugation, and conflicts with the currently accepted definition of that term.
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1120 (https://doi.org/10.1351/pac199466051077)