With all of the discussion, I'd like to interject one definition of
'deal' which I read in an English furniture maker's diary.  He lived
in the mid 1700s, and emigrated to 'The Colonies'.

He told of 'deal' as being any soft wood which was unfinished -- thus
cabinet backs, inside shelves, drawer bottoms, etc. were referred to
as 'deal'.  As opposed to the term 'deal' as a specific type of wood,
rather as a finish, or in this case a lack thereof.

Regards,
Bob Loesch
http://home.jps.net/~rrloesch/index.htm