In philosophy of science, concept formation and reduction is usually discussed with respect to definability. In the paper at hand this discussion is slightly expanded to an investigation of concept formation and reduction by analogies. It is argued that many kinds of such analogies bear some important features of partial contextual definitions. With the help of a detailed investigation of the so-called gene-meme-analogy it is then demonstrated how the "meme" concept is introduced via analogies into an expanded theory of (cultural) evolution. As a consequence it is shown that the diversity of meanings of the "meme" concept fits into the current state of establishing this analogy.