Noah Webster's New International Dictionary of the English Language

1. (v. i.) Act of departing; departure.

2. (n.) A part, portion, or subdivision.

3. (n.) A distinct course of life, action, study, or the like; appointed sphere or walk; province.

4. (v. i.) Subdivision of business or official duty; especially, one of the principal divisions of executive government; as, the treasury department; the war department; also, in a university, one of the divisions of instruction; as, the medical department; the department of physics.

5. (n.) A territorial division; a district; esp., in France, one of the districts composed of several arrondissements into which the country is divided for governmental purposes; as, the Department of the Loire.

6. (n.) A military subdivision of a country; as, the Department of the Potomac.