phraseology n.

1520s, "manner or style of expression," also "brief expression with some unity; two or more words expressing what is practically a single notion," from Late Latin phrasis "diction," from Greek phrasis "speech, way of speaking, enunciation, phraseology," from phrazein "to tell, declare, indicate, point out, show, inform," also passively (phrazomai), "indicate to oneself, think or muse upon, consider; think up, contrive; suppose, believe, imagine; perceive, observe."

The Greek verb is of uncertain origin; perhaps it is connected with phrenes "wits, senses, sanity," phrēn "the mind, the heart," literally "midriff, diaphragm" (see phreno-). The musical sense of "a short and somewhat independent passage from a piece" is from 1789. Phrase-book "collection of expressions peculiar to a language" is by 1590s.

word-forming element meaning "a speaking, discourse, treatise, doctrine, theory, science," from Greek -logia (often via French -logie or Medieval Latin -logia), from -log-, combining form of legein "to speak, tell;" thus, "the character or deportment of one who speaks or treats of (a certain subject);" from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Often via Medieval Latin -logia, French -logie. In philology "love of learning; love of words or discourse," apology, doxology, analogy, trilogy, etc., Greek logos "word, speech, statement, discourse" is directly concerned.