A practice agreed rather than required. A convention is not a rule, and treating it as one is a common error.

The name by which a stored thing is known and found. In this library, the filename is the parse.

The word by which a thing is called and known. A name is given rather than found — which is why it can be wrong, and why it can be chosen.

The name a person is known by within a system. Chosen rather than given, and often more theirs than their legal one.