A backend model is usually just called the model as it’s modeling the data domain (sometimes called ‘domain model’). The thing you pass to the frontend is the ‘view model’ which is often entirely different.

In some CRUD situations though, they can be nearly the same and you can convert the domain model into a specific view model with some kind of adapter (how people do this varies a lot). This adapter will take the end user security level into account, for example. Also, to avoid sending lots of useless data for a list, you can have a list view model. But if you do that, be sure to either keep the two in sync, or you have one and keep track of whether it’s partially or fully hydrated.