'To deal in futures' definitions:

Definition of 'To deal in futures'

From: GCIDE

Future \Fu"ture\, n. [Cf. F. futur. See Future, a.] [1913 Webster]
1. Time to come; time subsequent to the present (as, the future shall be as the present); collectively, events that are to happen in time to come. "Lay the future open." --Shak. [1913 Webster]
2. The possibilities of the future; -- used especially of prospective success or advancement; as, he had great future before him. [1913 Webster]
3. (Gram.) A future tense. [1913 Webster]
To deal in futures, to speculate on the future values of merchandise or stocks. [Brokers' cant] [1913 Webster]