  We define two words in a language to be connected if they express similar
concepts. The network of connections among the many thousands of words that
make up a language is important not only for the study of the structure and
evolution of languages, but also for cognitive science. We study this issue
quantitatively, by mapping out the conceptual network of the English language,
with the connections being defined by the entries in a Thesaurus dictionary. We
find that this network presents a small-world structure, with an amazingly
small average shortest path, and appears to exhibit an asymptotic scale-free
feature with algebraic connectivity distribution.
