The noun department has 3 senses (first 1 from tagged texts)
1. (28) department, section -- (a specialized division of a large organization; "you'll find it in the hardware department"; "she got a job in the historical section of the Treasury")
2. department -- (the territorial and administrative division of some countries (such as France))
3. department -- (a specialized sphere of knowledge; "baking is not my department"; "his work established a new department of literature")