Synonyms for Pleat (same or very similar meaning)
WordNet sense 1 (any of various types of fold formed by doubling fabric back upon itself and then pressing or stitching into shape):
plaitWordNet sense 2 (pleat or gather into a ruffle):
ruffleWordNet sense 3 (fold into pleats):
plicateFrom the ODE community, based on WordNetadd/edit