This relationship of meronymy is controversial for various reasons. First, there are several types of meronymy, such as functional meronymy, where one concept is a functional part of another (e.g. FINGER-HAND) or more general part-whole relations, where the part and the whole exist as a continuous entity (e.g. FLAME-FIRE). Secondly, there are diverging opinions as to whether meronymy should be treated as a semantic primitive in the sense of [syn]onymy, antonymy, and hyponymy.