DAU - A representation of an actual or conceptual system that involves mathematics, logical expressions, or computer simulations that can be used to predict how the system might perform or survive under various conditions or in a range of hostile environments.
ISO 16792 - Combination of design model, annotation and attributes that describes a product.
NAS 9300-007 - A description or representation of a system, entity, phenomena, or process (adapted from Banks, J., ed. (1998). Handbook of Simulation. New York: John Wiley & Sons). A model may be constructed from multiple sub-models; the sub-models and the integrated sub-models are all considered models. Likewise, any data that goes into a model is considered part of the model. A model of a model (commonly called a metamodel), e.g., a response surface constructed from the results of M&S, is considered a model.
MBE Maturity Index - [Primary] A digital representation of a thing.
[Alt] See 3D model.