noun
bento shop; lunch vendor
A shop or person that sells boxed lunches (bento). Can refer to a standalone store, a stall, or a delivery service.
駅前の弁当屋で幕の内弁当を買った。
I bought a makunouchi bento at the bento shop in front of the station.
食堂 is a general dining hall or cafeteria where you can eat in, while 弁当屋 primarily sells takeaway boxed lunches.
Compound of 弁当 (bento, boxed lunch) and 屋 (shop, vendor).