Sorry been tied up.....Fidelity is actually the perfect word and what high fidelity audio is all about. Here is the definition: "the degree of exactness with which something is copied or reproduced" So a component higher in fidelity is truer to the source, musical event, actual sound of the instrument or voice etc....
They sound more real and deliver more high fidelity. Horns sound more as they should etc... Hope this helps.