1. Full size 'model' or replica of a good, machine, publication, etc., built to the exact dimensions of the intended item. A dummy serves as a physical example of the size, shape, layout, outlook, and other elements of the actual thing to be produced.
2. Party to a transaction who has not economic interest in it, but participates to achieve a legitimate objective such as holding a property's title on behalf of another party.
3. Fictitious activity (which has zero duration) used in project planning where two or more activities have the same starting and ending nodes.