Okay, so let's talk about the inverted breve. Do you know what a breve is? It's a little symbol that looks like a smile on top of a note. A breve tells you how long to hold a note when you're playing music.
Now, the inverted breve is just like a regular breve, but it's turned upside-down! It looks like a frown on top of a note.
When we see an inverted breve in music, it means that we should play a note shorter than a regular breve. In fact, it's usually about half as long as a regular breve.
So, just remember that the inverted breve is a frown on top of a note, and it means to play the note shorter than if it had a regular breve. Easy peasy!