The term ‘cap’ is used to refer to a player’s appearance in an international game. So, one says that “Luis Figo has 80 caps” (which is quite a few, by the way). I’ve always wondered about the origin of the term, and I found it here:
In the “old” days (e.g., 1900), when a team would go (i.e., sail) to another country to play, the hosting team would give each member of the visiting team a brimmed hat as a symbol of goodwill. Today, caps are not exchanged, but the term “cap” continues to represent games against foreign teams, where you represent your country. There are no formal rules that say you must be playing on foreign soil when you represent your country or that you must be a member of the country’s national team in order to get “capped”.
Any player with more than 100 caps would be a storied veteran.