Scope
The scope of the project is defined based on the client requirement and these represent the boundaries of the project.
A scope is a high-level definition which includes the requirement and its detailed boundaries and deliverables. Any change in a requirement in turn managed by the change of scope of the project.
In general, the scope of the project is defined to keep the team to be focused on the key deliverable and what matters and ruling out the other information mentioned by the client.
Scope models are used to represent the change, control, solution or a need.
The scope can also be used to change any limit of the boundary of the system.
In scope
They are the statements that define the capability, interfaces, and process in the solution.
Out of scope
The out of scope is in general anything that is not relevant to the solution and key consideration for this is to imagine the bigger picture of the project and to project out the irrelevant information to the solution.
For example, if we consider a boundary for the proposed solution the all the in-scope falls inside the boundary and rest all out of and known as out of scope.
Along with the definition of scope, we also have to define the assumptions and constraints and the risks associated.