plication

(noun) an angular or rounded shape made by folding. Synonyms: fold, crease, flexure, crimp, bend. Examples: "A fold in the napkin." "A crease in his trousers." "A plication on her blouse." "A flexure of the colon." "A bend of his elbow."

(noun) the act of folding in parallel folds. Synonyms: pleating.