pleat (n.) Look up pleat at Dictionary.com
"a fold," 1580s, variant of plait (n.). With a gap in the printed record 17c.-18c., but probably it was in continuous oral use.
pleat (v.) Look up pleat at Dictionary.com
1560s, used as the verb version of plait (n.) and probably representing an alternative pronunciation. Related: Pleated; pleating.