I am familiar with it in the aerospace industry. Digital Twin implies a higher degree of fidelity in terms of importing data from sensors and modeling of physics than just model or simulation might apply, even though it is a model and simulation.
For GE's digital twins in the jet engines, they will build a high fidelity representation of the each individual engine based on as built parts, and then they will simulate every flight based on accelerometers, force sensors, humidity sensors, temperature and pressure sensors which they have placed in the engine. This is different from a general model or simulation which will build a model from CAD and then have a series of expected flight simulations and use that to predict life of the engine.
For GE's digital twins in the jet engines, they will build a high fidelity representation of the each individual engine based on as built parts, and then they will simulate every flight based on accelerometers, force sensors, humidity sensors, temperature and pressure sensors which they have placed in the engine. This is different from a general model or simulation which will build a model from CAD and then have a series of expected flight simulations and use that to predict life of the engine.