  A thesaurus is one, out of many, possible representations of term (or word)
connectivity. The terms of a thesaurus are seen as the nodes and their
relationship as the links of a directed graph. The directionality of the links
retains all the thesaurus information and allows the measurement of several
quantities. This has lead to a new term classification according to the
characteristics of the nodes, for example, nodes with no links in, no links
out, etc. Using an electronic available thesaurus we have obtained the incoming
and outgoing link distributions. While the incoming link distribution follows a
stretched exponential function, the lower bound for the outgoing link
distribution has the same envelope of the scientific paper citation
distribution proposed by Albuquerque and Tsallis. However, a better fit is
obtained by simpler function which is the solution of Ricatti's differential
equation. We conjecture that this differential equation is the continuous limit
of a stochastic growth model of the thesaurus network. We also propose a new
manner to arrange a thesaurus using the ``inversion method''.
