the set of methods and principles that you use when studying a particular subject or doing a particular kind of work
A methodology is a system of methods and principles for doing something, for example for teaching or for carrying out research. (FORMAL)
Oxford Dictionary of Computing 5th
1. In general, a coherent set of methods used in carrying out some complex activity. The word is most frequently used in terms such as programming methdology or (system) design methodology. In the UK the word method is usually preferred for this meaning.
2. (especially in the UK) The science or study of method.
Concise Oxford 英英辞典
a system of methods used in a particular fieldd.
a set of methods and principles used to perform a particular activity.