This is a belt. You wear it around your waist. But what could under your belt mean?
Under Your Belt 已有的成就、经验或阅历 Dan: I tried making baguettes for my mom's birthday. It did not go well.Anna: Dan, why didn't you ask me for help? I have years of baguette baking under my belt.Dan: Baguettes under your belt? That's funny!Anna: This is no joke, Dan. Do you want my years of experience baking baguettes, or not?Dan: Sorry, yes. No, no joke. Anything under your belt is something you've already achieved or learned. For example, I have many many English in a Minute episodes under my belt. So I know my idioms. And that's another English in a Minute!