a branch of knowledge or study deal

a branch of knowledge or study dealing with a body of facts or truths systematically arranged and showing the operation of general laws:
the mathematical sciences.
2.
systematic knowledge of the physical or material world gained through observation and experimentation.
3.
any of the branches of natural or physical science.
4.
systematized knowledge in general.
5.
knowledge, as of facts or principles; knowledge gained by systematic study.
6.
a particular branch of knowledge.
7.
skill, especially reflecting a precise application of facts or principles; proficiency.