Rosch s prototype theory is a cognition-based categorization theory which was born as a reaction toAristotelian view of categorization which has been acknowledged for centuries. Contrary to the Aristotelian view,Rosch claimed that internal structure of a category is not homogeneous, i.e. it has a prototype, good and badmembers. Category boundaries are not clear cut and they have transition zones which means that the category isalways open to new members. There are a typical member named as prototype in the center and other peripheralmembers ranking in a hierarchical order, steadily having less representative attributes. Prototypes have someprivileges; they are the cognitive reference points, they are easily retrieved and they belong to the basic levelcategory, which children learn first while acquiring their mother tongue. In the experimental part of the research,a group of 210 subjects formed by children, teenagers and adults have been asked for to write down seven typicalexamples under 22 concrete and abstract category names. The results, within the scope of the research, showedthat, the semantic categories in Turkish are formed around prototypes. However, some differences betweenabstract and concrete categories have been detected.