be (not) (one's) department

To be one's area of expertise or responsibility. I can't approve expense reports—that's not my department. Car repair is my dad's department, so he should be able to help you out.

Common Names:

Name	Pronounced	Usage
Rodney	['rɔdni]
Samo	-	Slovene, Medieval Slavic
Stanislava	stah-nee-SLAH-vah (Russian)	Czech, Slovak, Bulgarian, Serbian, Croatian, Slovene, Russian, Medieval Slavic
Emigdia	-	Spanish
Breindel	-	Yiddish
Dugald	-	Scottish