What is pitch?

Pitch may refer to several things, the first of which is a quality of sound. The pitch of sound refers to how high or low we perceive a sound to be based on the frequency of the sound waves. Pitch is also the term used to describe a kind of resin derived from burning plants or which results from decayed organic matter. We also call this viscous substance tar, asphalt, or bitumen, and it may be used to seal roads or structures. As a verb, pitch can refer to throwing, as in baseball. Finally, the term "pitch" may also be used to describe an incline or slope of some kind. In flight, rotation around the side-to-side axis, which creates a slope, is called pitch.