department-n; 3 Senses

Sense Number 1: specialized division of a larger organization

Commentary: DEPARTMENT[+entity][+organization][+division][+specialized] a specialized division of a large organization

You'll find it in the hardware department.
He works for the department of energy.
The music department is located on the sixth floor of Williams Hall.
Our department doesn't process these forms, you need to go to accounting.
Mary's sister works in cosmetics at a local department store.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: territorial administrative division

Commentary: DEPARTMENT[+location][+geographical][+territory][+division][+administered][+principal] the territorial and administrative division of some countries (such as France)
NOTE: refers to larger divisions (territories) than Sense 1 (organizations)

There are a number of regional administrative departments across France.
Several departments were set up across the occupied nation.

WordNet 3.0 Sense Numbers: 2

Sense Number 3: specialty, scope of responsibility or ability

Commentary: DEPARTMENT[+environment][+social][+scope][+responsibility/+ability] a specialized sphere of knowledge or responsibility

Walking the dog is my department, feeding the cat is his.
He is lacking in the trustworthiness department. (informal)
John thinks Mary is tops in the looks department. (informal)

WordNet 3.0 Sense Numbers: 3