The Collaborative International Dictionary of English v.0.48:
Dolly \Dol"ly\, n.; pl. Dollies.
1. (Mining) A contrivance, turning on a vertical axis by a
handle or winch, and giving a circular motion to the ore
to be washed; a stirrer.
2. (Mach.) A tool with an indented head for shaping the head
of a rivet. --Knight.
3. In pile driving, a block interposed between the head of
the pile and the ram of the driver.
4. A small truck with a single wide roller used for moving
heavy beams, columns, etc., in bridge building.
5. A compact, narrow-gauge locomotive used for moving
construction trains, switching, etc.