n. A three-dimensional copy or representation of something in which all parts have dimensions in the same proportion to that of the original.
A scale model is most generally a physical representation of an object, which maintains accurate relationships between all important aspects of the model, although absolute values of the original properties need not be preserved. This enables it to demonstrate some behavior or property of the original object without examining the original object itself. The most familiar scale models represent the physical appearance of an object in miniature, but there are many other kinds.
Scale models are used in many fields including engineering, architecture, film making, military command, salesmanship and hobby model building. While each field may use a scale model for a different purpose, all scale models are based on the same principles and must meet the same general requirements to be functional. The detail requirements vary depending on the needs of the modeler.
To be a true scale model, all relevant aspects must be accurately modeled, such as material properties, so the model's interaction with the outside world is reliably related to the original object's interaction with the real world.