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general::
Also, . a great deal. See under GOOD DEAL., Also, a great deal. 1. A large but indefinite quantity, as in He has a good (or great) deal of money; also, to a large extent or degree, as in "I bled . . . a great deal" (from Daniel Defoe's Robinson Crusoe, 1719). Also see GOOD MANY. 2. A very successful transaction or business agreement; a bargain. For example, The new agent got him a great deal, or Only $50,000 for all that land? That's a good deal. [Colloquial; mid-1800s]
American Heritage Idioms