Aristotle on Rhetoric

Now, the framers of the current treatises on rhetoric have
constructed but a small portion of that art. The modes of persuasion
are the only true constituents of the art: everything else is merely
accessory. These writers, however, say nothing about enthymemes, which
are the substance of rhetorical persuasion, but deal mainly with
non-essentials.

enthymeme
n.
L enthymema < Gr enthymcma < enthymeisthai, to consider, reflect upon < en3, in + thymos, mind < IE *dhdmos < base *dheu3 > DULL6 Logic a syllogism in which one of the premises or the conclusion is not expressed but implied
en#thy[me[mat4ic 730! mc mat4ik8
adj.