Defining a deli or delicatessen is not always easy. Many of them are small shops owned by one family. These shops have often been in the same family for years or even generations. They all sell a variety of pre-cooked meats and offer cheeses to go with the meats. Some of them also offer a variety of other foods to go along with the meats. These can include, but are not limited to, specialty olives and oils, spices, chutneys and breads.
There are no rules that say what a deli can serve or must serve. The basics seem to be already prepared meats and cheeses. After that, it is up to the owner what else they have on offer. Delis are often small shops. They have very little front counter room. Those that offer seating for customers are often rare, but they are busy places if their food is good. Many of the items sold in delis are cooked on the premises and made completely from scratch. Most successful delis use old family recipes to make their best foods.