A sushi restaurant is one (service business) which serves mainly sushi (especially nigirizushi [sushi shaped by hand]), but it is critically different from other restaurants in that freshness counts because the food materials include many perishables like sashimi (fresh slices of raw fish).
寿司屋は、寿司（特に寿司握り寿司）を主として供する飲食店（サービス業）ではあるが、刺身を含め食材に生のものが多く鮮度も重視される点で、他の飲食店と決定的に異なる。