Trop is a figure of speech. A word or utterance is used in a figurative (not literal) sense.
Metaphor, metonymy, synecdoche are among the most common tropes.
Metaphor is sometimes used in a very broad sense as a synonym for trope (ie, a term covering all figures of speech). It is also used in a narrower sense to denote a particular figure of speech.
The identification and analysis of the most important tropes was a major occupation in classical rhetoric. In this and other aspects, classical rhetoric is valued by modern semiotics.
Here, as in so many other contexts (for example, in logic and linguistics), the study of signs is also undertaken, though not under the name of semiotics and not with the conscious aim of creating a general theory.
