Antonomasia

Antonomasia is like a nickname. It's a word that is used instead of a longer phrase or name. For example, someone might say "I'm going to watch a movie" but instead of saying the full name of the movie, they might use a nickname - like saying "I'm going to watch The Avengers" instead of saying "I'm going to watch Marvel's The Avengers". Antonomasia is sort of like shorthand for saying something a bit more quickly.