A financial risk or venture; a commercial enterprise; a speculation. Also as a mass noun: the action or fact of pursuing such an undertaking.

An enterprise of a business nature in which there is considerable risk of loss as well as chance of gain; a commercial speculation.

An act or instance of speculating; a commercial venture or undertaking of an enterprising nature, esp. one involving considerable financial risk…

A commercial speculation or venture.

Originally U.S. A business transaction, esp. of a speculative kind: cf. operate, v. 9. Also: a business venture or enterprise.

Oil Industry (originally U.S.). An investment or development opportunity; a commercial venture the success of which depends upon speculation.