A "tuna sandwich" is a kind of sandwich that is made with tuna fish, where tuna is mixed with mayonnaise and other ingredients and then placed between two slices of bread. Full definition
I originally thought I would make tuna sandwiches, but then remembered these egg salad sandwiches and realized I hadn't made them in a long time. (confessionsofacookingdiva.com)
Eating tuna sandwiches at your desk is a quick road to nothing. (lawyerist.com)
I do, but the same old tuna sandwich can get boring after a while. (jessicalevinson.com)