CriticaLink | Aristotle: Poetics | Guide to Book XXI
Uses of Words Aristotle identifies several categories into which the words used in tragedies can be separated: current words, strange words, metaphors, ornamental words, and altered words. Current words are those spoken by persons living in the region in which the tragedy is composed and performed; strange words are foreign terms and loan-words. The meanings of most of these designations are obvious.
Aristotle's discussion of metaphor is characteristically precise. The following diagrams might help to understand the different types of metaphor he describes. The examples are correspond to the ones Aristotle provides.Genus to Species
Species to Genus
Species to Species