Many people, of course, rely upon dictionaries to provide definitions for concepts. Unfortunately, lexicographers do not necessarily follow the precise logical procedure we have described. Consequently, the dictionary is at best a guide—not an ultimate authority on meanings and definitions. Dictionaries can be very useful, however, in determining which word should be associated with a given concept. Although we have seen that valid concepts are determined not by social convention but by objective facts of reality, the assignment of a particular word to each concept is primarily a matter of convention (a point which will be elaborated later). The dictionary is an excellent guide to such conventional usage.

In order to clarify the meanings of concepts used in this course, the most important and difficult terms are defined or explained in the Glossary, with which the student should by now be familiar. The Glossary, reached from the Review window, includes references to pages in which terms are introduced or discussed and links between terms. Links are also provided to referenced pages that were covered earlier in the course.