E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
in theatrical slang, means properties, of which it is a contraction. Everything stored in a theatre for general use on the stage is a prop, but these stores are the managers props. An actors props are the clothing and other articles which he provides for his own use on the stage. In many good theatres the manager provides everything but tights and a few minor articles; but in minor theatres each actor must provide a wardrobe and properties.