diction vs phraseology

diction and phraseology both are nouns.

Word	Noun	Adjective	Verb	Adverb
diction	Yes	No	No	No
phraseology	Yes	No	No	No

As nouns, diction and phraseology are synonyms defined as:

diction and phraseology: the manner in which something is expressed in words

Other synonyms of diction include choice of words, phrasing, verbiage, wording.

diction (noun)	phraseology (noun)
the manner in which something is expressed in words	the manner in which something is expressed in words
the articulation of speech regarded from the point of view of its intelligibility to the audience