"board made of two or more thin layers of wood bonded together and arranged so that the grain of one runs at right angles to that of the next," 1907, from ply (n.) + wood (n.).
Entries linking to plywood
ply n.
"a layer, a fold," 1530s, from French pli "a fold" (13c.), alteration of Old French ploi "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"). Often used to indicate the number of thicknesses of which anything is made; this also is the ply in plywood.
wood n.
Old English wudu, earlier widu "tree, trees collectively, forest, grove; the substance of which trees are made," from Proto-Germanic *widu- (source also of Old Norse viðr, Danish and Swedish ved "tree, wood," Old High German witu "wood"), from PIE *widhu- "tree, wood" (source also of Welsh gwydd "trees," Gaelic fiodh- "wood, timber," Old Irish fid "tree, wood"). Out of the woods "safe" is from 1792.