metaphorical extension

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A noun meaning the process as the language changes over time in linguistics wherein the meaning of or part of the sense of a word which was used as a portion of a popularized metaphorical phrase is transferred back to and subsequently becomes one of the accepted general meanings of the original word used in the phrase . (Example mouse, in computing from computer mouse, an input device which possessed a metaphorical tail.)
• noun The part of the definition of a word which has undergone a such meaning change.