No, “cap” in football is not a short form or abbreviation of another word. It literally comes from the tradition of awarding a physical cap (hat) to players each time they played for their national team.
Over time, people stopped giving actual hats for every match, but the term “cap” stuck to mean an international appearance.
So when you see “He has 50 caps for England,” it simply means he has played 50 times for the England national team.
If you want, I can also explain why people sometimes confuse it with “capture” or “capital” in other sports contexts—it’s a funny historical quirk. Do you want me to?
