double duty
nounUK /ˌdʌb.əl ˈdjuː.ti/
US /ˌdʌb.əl ˈduː.ti/
When one thing does two jobs at the same time.
This sofa does double duty as a bed for guests.
RELATED WORDS
OTHER MEANINGS
2. A job or shift that is worked in addition to one's regular work.
She took on double duty at the hospital during the holiday rush.
3. Two responsibilities carried by the same person at once.
As coach and parent, he was pulling double duty at the game.
4. A fabric or item made to be strong enough for two kinds of wear.
These double-duty boots are built for both hiking and work.