1. Determining the physical dimensions of an object or location, and/or sorting into categories. 2a. noun. Scenic. Sizing or size. A solution involving starch and often whiting used to prepare a canvas or muslin surface for painting, as on a Broadway Flat. 2b. verb. Scenic. To use the above. To apply sizing, or to size the flats. Traditionally, a solution of hot water and Argo Laundry Starch, OR a dilution of water and animal glue was used.