What does "dolly" mean?

Additional senses

1. 2.In pile driving, a block interposed between the head of the pile and the ram of the driver.
2. 3.A small truck with a single wide roller used for moving heavy beams, columns, etc., in bridge building.
3. 4.A compact, narrow-gauge locomotive used for moving construction trains, switching, etc.
4. 5.A child's mane for a doll. Dolly shop, a shop where rags, old junk, etc., are bought and sold; usually, in fact, an unlicensed pawnbroker's shop, formerly distinguished by the sign of a black doll. [England]