Imagine an organisation as a set of entities or functions that in their smallest unit add a value to the output and existence of that organisation.
Grouping these essential functions in an organisational structure (formally or less formally) is one of the things management and leadership do.
The choices made influence how the organisation is perceived, even if the basic functional entities remain unchanged (which is often the case in organisational changes).
Drawing the lines is not without meaning and that is something to remember when involved in organisation design.