a large flat board on which paper may be spread for artists or designers to work on.
back to the drawing board
used to indicate that an idea, scheme, or proposal has been unsuccessful and that a new one must be devised:the government must go back to the drawing board and review the whole issue of youth training
on the drawing board
(of an idea, scheme, or proposal) under consideration and not yet ready to put into practice:there are plans to enlarge the runway, but at present all this remains on the drawing board
drawing board in other Oxford dictionaries
Definition of drawing board in the US English dictionary