protective covering consisting, for example, of a layer of boards applied to the studs and joists of a building to strengthen it and serve as a foundation for a weatherproof exterior
an extended communication (often interactive) dealing with some particular topic; "the book contains an excellent discussion of modal logic"; "his treatment of the race question is badly biased"
an exchange of views on some topic; "we had a good discussion"; "we had a word or two about it"