Sentence:  If the robin is the <WSD>prototype</WSD> of bird, do particular examples of robin constitute that <WSD>prototype</WSD> for different people? I think not. Rather, <WSD>prototypes</WSD> are themselves categories. Thus, to say that a robin is a prototypic bird is to propose that a class of similar creatures called "robin" is a <WSD>prototype</WSD> of bird. 
Meaning of the word marked with <WSD> tags:  An instance of a category or a concept that combines its most representative attributes.