phraseology -
A group of specialized words and expressions used by a particular group.
phraseology -
A collection of phrases; a phrasebook.
Wikipedia
Phraseology appeared in the domain of lexicology and is undergoing the process of segregating as a separate branch of linguistics. The reason is clear – lexicology deals with words and their meanings, whereas phraseology studies such collocations of words (phraseologisms, phraseological units, idioms), where the meaning of the whole collocation is different from the simple sum of literal meanings of the words, comprising a phraseological unit. F.e. ‘Dutch auction’ is not an auction taking place in Netherlands.