millboard

[ mil-bawrd, -bohrd ]

/ ˈmɪlˌbɔrd, -ˌboʊrd /

a strong, thick pasteboard used to make book covers.

Origin of millboard

First recorded in 1705–15; mill(ed) + board

Cut a piece of millboard, celluloid, or even thin wood the same size, and upon this paint an attractive design.

Three Hundred Things a Bright Boy Can Do |Anonymous
The hollow between the neck and shell is filled with millboard.

The Girl's Own Paper, Vol. VIII, No. 354, October 9, 1886 |Various
He began his career as a painter when a mere boy; though not upon canvas, millboard nor panel, but upon watering-cans.

Curiosities of Impecuniosity |H. G. Somerville
The covering incase of the packet was a kind of stiff cardboard or millboard, within brown paper.

In Luck at Last |Walter Besant

A is the piece of millboard, B the sheets of paper, C the strip.

Three Hundred Things a Bright Boy Can Do |Anonymous

millboard

/ (ˈmɪlˌbɔːd) /

strong pasteboard, used esp in book covers

C18: changed from milled board