@prefix gacs: . @prefix skos: . @prefix rdfs: . @prefix owl: . @prefix rdf: . @prefix dc: . gacs:C4914 skos:definition gacs:def_91d560f1 . rdfs:label "Concept definition"@en ; a owl:Class . gacs:def_91d560f1 rdf:value "To lower the pH of a substance or material to below 7.0"@en ; dc:source ; a .