in ballet, 1892, from French plié, from plier literally "to bend," from Old French ploier "fold, pleat, layer" (12c.), verbal noun from ployer (later pleier) "to bend, to fold," from Latin plicare "to fold, lay" (from PIE root *plek- "to plait").
-plex
Plexiglas
plexus
pliable
pliant
plie
plier
pliers
plight
Plimsoll
plink