Definite pitch

Have you ever heard a whistle or someone playing a guitar? The sounds they make are called pitches. A definite pitch means that the sound always stays the same and doesn't change. For example, if someone plays a guitar string and it makes a sound that is supposed to be an "A", it will always make that same "A" sound every time they play it. It doesn't change to a different sound. Just like if you sing "Twinkle, Twinkle, Little Star" and try to sing it higher or lower, it won't sound right because the pitch needs to stay the same for the song to sound good. A definite pitch helps us make music and understand what sounds we are hearing!