Digital Twin
Digital Twin Consortium :
A digital twin is a virtual representation of real-world entities and processes, synchronized at a specified frequency and fidelity.
See Also:
Digital Thread, Model, Data
Alternate Definitions:

Siemens - A digital twin is an exact, virtual representation of a product or process used to virtually validate the performance of its physical counterpart.

DAU - An integrated multiphysics, multiscale, probabilistic simulation of an as-built system, enabled by Digital Thread, that uses the best available models, sensor information, and input data to mirror and predict activities/performance over the life of its corresponding physical twin.

MBE Maturity Index - A model digitally connected with its realization(s).

CIMdata - A physics-based description of a system resulting from the generation, management, and application of data, models and information from authoritative sources across the system’s lifecycle.

DODI 5000.97 - A computerized representation (integrated set of models) that serves as the real-time digital counterpart of a physical object or process.