Eki 駅 - railway station
Bento 弁当 - Lunchbox
Ekiben is the name given to prepared lunchboxes, sold from stalls in railway station concourses and platforms. You can buy identical looking bento boxes from supermarkets and convenience stores too, even in restaurants, though there they are likely to be nice lacquer trays instead of cheap throwaway plastic. But only bento boxes bought from railway stations are ekiben.
The contents of bento boxes varies but typically there is rice, sometimes noodles instead, fish or meat, breadcrumbed with a worcester-like sauce or plain with soy sauce, vegetables (beans, bamboo shoot, tofu), cakes of unidentified processed seafood, and pickles.
This Ekiben was bought from a stall in Hiroshima Station for ¥840.