scaleboard

[ skeyl-bawrd, -bohrd, skab-erd ]
/ ˈskeɪlˌbɔrd, -ˌboʊrd, ˈskæb ərd /

noun

a very thin board, as for the back of a picture.
Printing. a thin strip of wood used in justifying.
a thin sheet of wood used as veneer.

Origin of scaleboard

First recorded in 1705–15; scale1 + board

British Dictionary definitions for scaleboard

scaleboard
/ (ˈskeɪlˌbɔːd, ˈskæbəd) /

noun

a very thin piece of board, used for backing a picture, as a veneer, etc