New Latin phraseologia, irregular from Greek phrasis + -logia -logy
In linguistics, phraseology is the study of set or fixed expressions, such as idioms, phrasal verbs, and other types of multi-word lexical units (often collectively referred to as phrasemes), in which the component parts of the expression take on a meaning more specific than or otherwise not predictable from the sum of their meanings when used independently. For example, ‘Dutch auction’ is composed of the words Dutch ‘of or pertaining to the Netherlands’ and auction ‘a public sale in which goods are sold to the highest bidder’, but its meaning is not ‘a sale in the Netherlands where goods are sold to the highest bidder’. Instead, the phrase has a conventionalized meaning referring to any auction where, instead of rising, the prices fall.
The basic units of analysis in phraseology are often referred to as phrasemes or phraseological units. Phraseological units are (according to Prof. Kunin A.V.) stable word-groups with partially or fully transferred meanings ("to kick the bucket", “Greek gift”, “drink till all's blue”, “drunk as a fiddler (drunk as a lord, as a boiled owl)”, “as mad as a hatter (as a march hare)”). According to Rosemarie Gläser, a phraseological unit is a lexicalized, reproducible bilexemic or polylexemic word group in common use, which has relative syntactic and semantic stability, may be idiomatized, may carry connotations, and may have an emphatic or intensifying function in a text.