Stationary phase which has been immobilized on the support particles or on the inner wall of the column, e.g. by a physical attraction (coated stationary phase), by chemical bonding (bonded stationary phase), or by in situ polymerisation (cross-linked stationary phase) after coating.
Source:
PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 183 (https://doi.org/10.1515/pac-2017-0111)