Hey kiddo, do you like music? Well, one thing that's important in music is pitch. That means how high or low a sound is. If you sing a song and your voice goes up and down, that's pitch!
But sometimes there are instruments that don't have a specific pitch. They just make noise without going higher or lower. We call that "indefinite pitch".
Think about hitting a drum. It makes a noise, but it doesn't have a specific pitch like a piano or a guitar string. It's just a bang!
Other instruments with indefinite pitch include shakers, tambourines, and cymbals. They can make noise, but they don't have a specific note like the keys on a piano.
So, indefinite pitch is when an instrument makes noise without a specific note, like when you bang on a drum or shake a shaker. Cool, huh?