pleat vs plication

pleat and plication both are nouns.

Word	Noun	Adjective	Verb	Adverb
pleat	Yes	No	Yes	No
plication	Yes	No	No	No

As nouns, plication is a hypernym of pleat; that is, plication is a word with a broader meaning than pleat:

pleat: any of various types of fold formed by doubling fabric back upon itself and then pressing or stitching into shape
plication: an angular or rounded shape made by folding

Other hypernyms of pleat include bend, crease, crimp, flexure, fold.

pleat (noun)	plication (noun)
any of various types of fold formed by doubling fabric back upon itself and then pressing or stitching into shape	the act of folding in parallel folds
	an angular or rounded shape made by folding

pleat (verb)	plication (verb)
pleat or gather into a ruffle
fold into pleats