Greek key vs Greek fret

Greek key and Greek fret both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greek key	Yes	No	No	No
Greek fret	Yes	No	No	No

As nouns, Greek key and Greek fret are synonyms defined as:

Greek key and Greek fret: an ornamental pattern consisting of repeated vertical and horizontal lines (often in relief)

Other synonyms of Greek key include fret, key pattern.

Greek key (noun)	Greek fret (noun)
an ornamental pattern consisting of repeated vertical and horizontal lines (often in relief)	an ornamental pattern consisting of repeated vertical and horizontal lines (often in relief)