Its a starter or appetiser (first course). Sometimes you get melon with other things like Peachey mentioned in starters. It wouldn't be the main course.

It could be "melon and parma ham". That's a popular starter.

In Spain, as Peachey has said before, you can have melon with dry-cured Spanish ham (jamón serrano). It is very popular in summer, because it is served cold and it is a watering meal. You can also include melon in a salad. Of course, you can also have melon as a dessert.

Appetizer?