1. the contemplation or consideration of some subject: to engage in speculation on humanity’s ultimate destiny.
2. a single instance or process of consideration.
3. a conclusion or opinion reached by such contemplation: These speculations are impossible to verify.
4. conjectural consideration of a matter; conjecture or surmise: a report based on speculation rather than facts.
5. engagement in business transactions involving considerable risk but offering the chance of large gains, esp. trading in commodities, stocks, etc., in the hope of profit from changes in the market price.
6. a speculative commercial venture or undertaking.