A metaphorical extension is the "extension of meaning in a new direction" through popular adoption of an original metaphorical comparison.
Metaphorical extension is almost a universal and natural process in any language undergone by every word. In general, it's not even perceived in everyday usage as meaning change. When its least obvious, users don't even see it as extending the meaning of a word. Consider the example of illuminate: it originally meant "to light up" something dim or dark, but has evolved to mean "to clarify", "to edify". After a while these new meanings seem so natural as to be integral parts of the word, where senses such as "to celebrate" and "to adorn a page with designs" seem like more obvious additions.
Other articles related to "metaphorical extension, metaphorical":
... The use of bug to refer to a computer error in logic was a metaphorical extension that has become so popular that it is now part of the regular meaning of "bug ... ironically, the more modern wireless ones have lost the metaphorical tail entirely ...
Famous quotes containing the word extension:
“Slavery is founded on the selfishness of mans natureopposition to it on his love of justice. These principles are in eternal antagonism; and when brought into collision so fiercely as slavery extension brings them, shocks and throes and convulsions must ceaselessly follow.”
—Abraham Lincoln (18091865)