If a sentence or a word meaning is figurative, it expresses one thing and means another.
To illustrate this idea, we will use the example given by Deirdre Wilson and Robyn Carston in Metaphor and relevance. The literal meaning of the sentence 'Caroline is a princess' is that Caroline is a female member of a royal family. On the other hand, the figurative meaning would be that Caroline is a somewhat spoiled or indulged girl, used to being given special treatment, having her wishes granted, having people defer to her, being exempt from ordinary, everyday chores, etc.
Literal or figurative meaning takes place at lexical (lexical items), grammatical (sentences) and pragmatic level (utterances). Lexemes can be word-lexemes, such as dog, word-forms, such as dogs, or phrasal lexemes, such as put up with, pig in a poke, red herring, etc. These kind of lexemes tend to be either grammatically or semantically idiomatic, or both: either their idiomatic distribution throughout the sentences of the language or their meaning is unpredictable from the syntactic and semantic properties of their constituents. When a semantically idiomatic phrasal lexeme, such as to kick the bucket, can be put into correspondence with a non-idiomatic phrasal expression, such as die, we way that the latter has a literal meaning, in contrast with the idiomatic, metaphorical or figurative meaning of the former.
1.1. Word levelFor Cruse, the default reading of a word is the one which comes to mind when the word is encountered out of context. Although this could be a valid principle for literalness, it might not always be a coincidence between default reading and literalness, as many examples show: expire means for most people the fact that an official document is not anymore valid, which is its most frequent though metaphorical sense. Thus, this is its default reading. Very few speakers would say that it means to die, although this is its literal meaning.
1.1.1. Established and non-established meaning extensionsAccording to Cruse, there are three kinds of extension: naturalized, established and nonce readings for words.
Naturalized extensions are those which speakers do not feel anymore as figurative meaning: The kettle is boiling; She's in love.
Established extensions are figurative, but speakers know they are using figures of speech. So, these meanings presumably have an entry in the mental lexicon: You, lazy bones, come on to work!; She had too many mouths to feed.
Finally, nonce readings have no entry in the mental lexicon, since these meanings are not yet collectively used, thus not being established. This is the province of individual creation of figurative meaning and it is usually generated and interpreted using strategies of meaning extension like metaphor and metonymy: I think I could eat an entire cow; This 5 euros note is my lunch today; We saw a giant caterpillar, grey and red, moving forward; The 6 p.m. train was passing.
1.2. Sentence and utterance level: metaphor and metonymyMetaphor and metonymy are the two most relevant figures of speech for semantic extension above the word level.
1.2.1. Metonymy versus metaphorMetonymy is one of the basic characteristics of cognition. It is extremely common for people to take one well-understood or easy-to-perceive aspect of something and use that aspect to stand either for the thing as a whole or for some other aspect or part of it.
Some common examples of metonymy are:"The pen is mightier than the sword" (pen is a metonym for writers and the exchange of ideas; sword is a metonym for war and violence).
"The White House", to refer to the US President and...