Similes and Metaphors - are similes a subset of metaphors?

Question

I've always been taught that metaphors and similes both draw a parallel between two disparate ideas/thoughts/objects, but that a simile is a more explicit comparison using the word "like" or "is", whereas a metaphor's connection is more implicit. For example, "His injured ankle burned like a hot stove" is a simile, where as, "His injured ankle was a hot stove of pain" is a metaphor.

However, I recently heard a colleague note that similes are nothing more than a special kind of metaphor. In other words, all similes are metaphors. This seems to contradict what I was always taught (and what I've read online, for what that's worth). Can anyone straighten me (or my colleague) out?

Answer 1

The Wikipedia article on Metaphor agrees with your colleague:

Metaphor also denotes rhetorical figures of speech that achieve their effects via association, comparison or resemblance (e.g., antithesis, hyperbole, metonymy and simile, which are all types of metaphor).

(emphasis added)

The article cites "The Oxford Companion to the English Language (1992) pp.653–55" as a reference for the above information, but I don't have access to that publication to verify the statement directly.

Edit: Well, it turns out that I do have access to that reference. Here it is, from p. 653, paragraph 2:

METAPHOR ... (1) All figures of speech that achieve their effect through association, comparison, and resemblance. Figures like antithesis, hyperbole, metonymy, simile are all species of metaphor.