Reference is made (in the Scholia on the Categoriæ, p. 43, b. 19) to a classification of names made by Speusippus, which must have been at least as early as that of Aristotle; perhaps earlier, since Speusippus died in 339 B.C. We do not hear enough of this to understand clearly what it was. Boêthus remarked that Aristotle had omitted to notice some distinctions drawn by Speusippus on this matter, Schol. p. 43, a. 29. Compare a remark in Aristot. De Coelo, i. p. 280, b. 2.] The first distinction pointed out by Aristotle among simple, uncombined Terms, or the things denoted thereby, is the Homonymous, the Synonymous, and the Paronymous. _Homonymous_ are those which are called by the same name, used in a different sense or with a different definition or rational explanation. _Synonymous_ are those called by the same name in the same sense. _Paronymous_ are those called by two names, of which the one is derived from the other by varying the inflexion or termination.[7] [Footnote 7: Aristot. Categor. p. 1, a. 1-15.] We can hardly doubt that it was Aristotle who first gave this peculiar distinctive meaning to the two words Homonymous and Synonymous, rendered in modern phraseology (through the Latin) _Equivocal_ and _Univocal_. Before his time this important distinction between different terms had no technical name to designate it. The service rendered to Logic by introducing such a technical term, and by calling attention to the lax mode of speaking which it indicated, was great. In every branch of his writings Aristotle perpetually reverts to it, applying it to new cases, and especially to those familiar universal words uttered most freely and frequently, under the common persuasion that their meaning is not only thoroughly known but constant and uniform. As a general fact, students are now well acquainted with this source of error, though the stream of particular errors flowing from it is still abundant, ever renewed and diversified. But in the time of Aristotle the source itself had never yet been pointed out emphatically to notice, nor signalized by any characteristic term as by a beacon. The natural bias which lead us to suppose that one term always carries one and the same meaning, was not counteracted by any systematic warning or generalized expression. Sokrates and Plato did indeed expose many particular examples of undefined and equivocal phraseology. No part of the Platonic writings is more valuable than the dialogues in which this operation is performed, forcing the respondent to feel how imperfectly he understands the phrases constantly in use. But it is rarely Plato's practice to furnish generalized positive warnings or systematic distinctions. He has no general term corresponding to homonymous or equivocal; and there are even passages where (under the name of Prodikus) he derides or disparages a careful distinctive analysis of different significations of the same name. To recognize a