The central result is that source meaning, target meaning, and common feature are three different analytical roles. Two sensory relata do not force a sensory common feature. Where at least one relatum is conceptual, the common feature must be characterized conceptually.
This lesson classified metaphor through its semantic structure. The next division asks instead about the linguistic form of the borrowed expression—whether it occurs as a noun, verb, derivative, or other grammatical form.
The semantic framework developed here will continue to apply, but the two taxonomic axes should not be collapsed into one.