plate
body that has two prevalent dimensions with respect to the third, therefore delimited by two parallel flat faces placed at a very small distance
ledger stone
horizontal tombstone
baffle
vane or panel for directing the flow of a fluid
plank
flat rectangular piece of timber
sheet metal
metal formed into thin, flat pieces, usually by an industrial process
stone slab
mostly elongated, rectangular stone with flat surface
overhead transparency
thin sheet of transparent flexible material to place on overhead projectors