"tropical banana-like tree or fruit," 1550s, plantan, from Spanish plátano, plántano, probably from Carib palatana "banana" (Arawak pratane), and altered by association with Spanish plátano "plane tree," from Medieval Latin plantanus "plane tree," itself altered (by association with Latin planta "plant") from Latin platanus (see plane (n.4)). So called from the shape of its leaves. There is no similarity or relation between this plant and plantain (n.2).
"common yard weed of the genus Plantago," with large, spreading leaves close to the ground and slender spikes, c. 1300, planteine, from Anglo-French plaunteyne, Old French plantain, from Latin plantaginem (nominative plantago), the common weed, from planta "sole of the foot" (see plant (n.)); so called from its flat leaves.
also *pletə-, Proto-Indo-European root meaning "to spread;" extension of root *pele- (2) "flat; to spread."
It forms all or part of: clan; flan; flat (adj.) "without curvature or projection;" flat (n.) "a story of a house;" flatter (v.); flounder (n.) "flatfish;" implant; piazza; place; plaice; plane; (n.4) type of tree; plant; plantain (n.2); plantar; plantation; plantigrade; plat; plate; plateau; platen; platform; platinum; platitude; Platonic; Plattdeutsch; platter; platypus; plaza; supplant; transplant.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit prathati "spreads out;" Hittite palhi "broad;" Greek platys "broad, flat;" Latin planta "sole of the foot;" Lithuanian platus "broad;" German Fladen "flat cake;" Old Norse flatr "flat;" Old English flet "floor, dwelling;" Old Irish lethan "broad."