Software process defines the phased activities or What to do in each phase, It does not specify how to perform the activities.
Software Methodology defines the detailed steps or how to carry out the activities of a process.
Software process specifies the input and output of each phase, but it does not dictate the representations of a input and output.
Methodology defines the steps, step entrance, and exit criteria, and relationships between the steps.
Methodology also specifies, for each step, procedures and techniques, principles and guidelines, step input and output, and representations of the input and output.