The definition of the term Methodology is not a consensus and the meaning may change from some knowledge domain to another.
Here I share my personal experience about it after helping dozens of companies do create and adapt their Solution Development Methodologies.
I hope it may help you as well.
This explanation was first shared in the BA Fringe (S2E4) presented by Adrian Reed from Blackmetrics. I just added some graphics to illustrate it better here at the #TheBrazilianBA Channel.