ion exchanger with cations as counter-ions. The term cation-exchange resin may be used in the case of solid organic polymers. The acid form of a cation exchanger is the ionic form of a cation exchanger in which counter-ions are hydrogen ions (H-form) or the ionogenic groups have added a proton forming an undissociated acid.
Source:
PAC, 1993, 65, 819. 'Nomenclature for chromatography (IUPAC Recommendations 1993)' on page 855 (https://doi.org/10.1351/pac199365040819)