I once told my mother about a specific incident that occurred in my highschool French class.
Eight years later, she mentions this incident again and this is one of those things that I would have never remembered unless someone else brought it up. Even if I tried my hardest to remember everything that happened in my French class, I would have never remembered this one because frankly, it was so inconsequential to my life.
Is there a word or phrase for this type of memory (where you don't remember something until someone else mentions it)?