See: active site (in heterogeneous catalysis)
Source:
PAC, 1976, 46, 71. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units - Appendix II. Definitions, Terminology and Symbols in Colloid and Surface Chemistry. Part II: Heterogeneous Catalysis' on page 77 (https://doi.org/10.1351/pac197646010071)
See also:
PAC, 1992, 64, 143. 'Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)' on page 145 (https://doi.org/10.1351/pac199264010143)