The in-universe Trope Namer.
Do We Have This One?? Show me if we do. Description help is wanted. And the YKTTW needs examples badly - I saw this one recently and I can't think of much else.
Sometimes, an event is remembered not just for what it was but who was involved in it; the relationship between "what" and "who" is so close that the person's name becomes a synonym for the event in question. This is something of the in-universe equivalent to a Trope Namer.