An avocation is a hobby or activity that you like to do for fun. It's something you do in your free time, just because you enjoy it. Let's say you like to draw pictures. You're not trying to make money from your drawings, you just enjoy creating them. That's an avocation! It's like having a secret superpower that you use to make yourself happy. Sometimes people turn their avocation into a career when they get older, but sometimes they just keep doing it as a hobby forever. The important thing is that it makes you happy!