The use of new words or new meanings for old words not yet included in standard definitions, as in the recent application of the word cool to denote, very good, excellent or fashionable. Some disappear from usage; others like hip and feedback, for example, remain in the language. (Compare Nonce Word, Portmanteau Word)
A neologism (from Greek Î½ÎµÎ¿Î»Î¿Î³Î¹ÏƒÎ¼ÏŒÏ‚ "Î½ÎÎ¿Ï‚" [neos] = new; "Î»ÏŒÎ³Î¿Ï‚" [logos] = word) is a word, term, or phrase which has been recently created ("coined") — often to apply to new concepts, to synthesize pre-existing concepts, or to make older terminology sound more contemporary. Neologisms are especially useful in identifying inventions, new phenomena, or old ideas which have taken on a new cultural context. The term e-mail, as used today, would be an example of a neologism.