Bill"board` (?), n.
1. Naut.
A piece of thick plank, armed with iron plates, and fixed on the bow or fore channels of a vessel, for the bill or fluke of the anchor to rest on.
Totten.
2.
A flat surface, as of a panel or of a fence, on which bills are posted; a bulletin board.
<-- esp. a large board on which the space is rented for advertising purposes. -->
© Webster 1913.