"to cover (something) with a layer of metal or mail," late 14c., platen, from plate (n.). Related: Plated.

"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.

also sand-paper, "stout paper with a fixed layer of sharp sand," 1788, from sand (n.) + paper (n.).

"nacreous inner layer of the shell of various bivalve mollusks," c. 1500, translating Medieval Latin mater perlarum, with the first element perhaps connected in popular imagination with obsolete mother (n.2) "dregs." Compare Italian madreperla, French mère-perle, Dutch parelmoer, German Perlmutter, Danish perlemor. It is the stuff of pearls but in a layer instead of a mass.

small slab of ice cream surrounded by a layer of fruit-flavored water ice and mounted on a stick, 1932, a trademark name, merger of ice-cream and Popsicle.