message: docs: add differential loading term to glossary
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diff: @@ -303,6 +303,14 @@ Learn more in [Dependency Injection in Angular](guide/dependency-injection).
  A lookup token associated with a dependency [provider](#provider), for use with the [dependency injection](#di) system.
  +{@a differential-loading}
  +
  +## differential loading
  +
  +A build technique that creates two bundles for an application. One smaller bundle is for modern browsers. A second, larger bundle allows the application to run correctly in older browsers (such as IE11) that do not support all modern browser APIs.
  +
  +For more information, see the [Deployment](guide/deployment#differential-loading) guide.
  +
  {@a directive}
  {@a directives}
  