(~s)
Note: in AM, use 'drawing-board'
1.
A ~ is a large flat board, often fixed to a metal frame so that it looks like a desk, on which you place your paper when you are drawing or designing something.
N-COUNT
2.
If you say that you will have to go back to the ~, you mean that something which you have done has not been successful and that you will have to start again or try another idea.
PHRASE: PHR after v