In philosophy, there are different ways of using the word ‟definition”. With respect to some of them, Bielik, Gahér and Zouhar have proposed a systematic logical-semantic classification. In this paper, I set out three basic methodological requirements for using the term ‟definition” within scientific classifications, and then I analyze the semantic classification with the resulting conclusion that two of the three types of definitions do not satisfy the requirements. Based on the analysis, the scientific model of classification is subsequently replaced by Wittgenstein's model of family resemblances.
Deference, Definition, Family resemblances, Logical semantics, Meaning definition, Normative definition