While the word "comparative" refers to a cognitive and intellectual activity supposing that there are several elements to compare, the word "law" is used in the singular, as if law was to be compared to itself The whole phrase indicates that comparison takes place within the study of the law, but the use of the singular does not point to a pluralistic approach: what do we mean by law? Should we not talk about "comparing the laws" or "legal comparison"? With a reflection on the words of the law as a starting point, this paper visits the corpus of comparative law in a pluralistic perspective and the process as a basic element of cognition. Words of the comparatists are then visited in successive steps describing what they do: first the discovery of the foreign legal system with immersion in its language and culture yet keeping some outsider awareness to read the silence in language. Then comes the need to communicate on this other legal system, which is in essence an experience in translation. Based on what they learn, comparatists also build systems, using or developing common words in the various realms of international law, often for practical purposes. Last but not least, some aspire to develop neutral terms for the sake of knowledge in order to develop a specialty language of legal science. This latter activity tends to be neglected as a utopian aspiration. It encompasses the creation of precise terms and meta-categories. In any case, words are the tool of comparatists and therefore constantly evolve.