The Commens Dictionary
Quote from ‘Syllabus: Nomenclature and Division of Triadic Relations, as far as they are determined’
… a Qualisign is any quality in so far as it is a sign. Since a quality is whatever it is positively in itself, a quality can only denote an object by virtue of some common ingredient or similarity; so that a Qualisign is necessarily an Icon. Further, since a quality is a mere logical possibility, it can only be interpreted as a sign of essence, that is, as a Rheme.