1. One who, or that which, propels. [ 1913 Webster ]
2. A contrivance for propelling a steam vessel, usually consisting of a screw placed in the stern under water, and made to revolve by an engine; a propeller wheel. [ 1913 Webster ]
3. A steamboat thus propelled; a screw steamer. [ 1913 Webster ]
Propeller wheel, the screw, usually having two or more blades, used in propelling a vessel. [ 1913 Webster ]