The goal of this paper is to reanalyze some notion of word-formation with priority given to word formation element by Kim(1996) and pseudo-affix by Song(2002) in Korean morphology and suggest new notion related to them. They have both merits and demerits. In oder to overcome the problem, I propose that there are two different levels in lexicon; word-formation level and word-analysis level. I suggest new notion for the former, so called participated element and fixed element, and root or affix belong to the latter. And I regard the process of word-formation as evolution, and this could be a clue for explanation meaning derivation in word-formation. In addition, I suggest the possibility that words would be connected like in network theory.