This document provides definitions and explanations of basic music theory terms: 1) It defines music as an art of sound and time, and defines sound as vibration perceived by the ear. It identifies the four characteristics of sound as pitch, intensity, duration, and timbre. 2) It defines pitch as the highness and lowness of a sound, and defines tone as a musical sound of definite pitch. It defines intensity as the loudness or softness of a pitch. 3) It discusses music notation, identifying the staff consisting of five lines and the use of clefs such as the treble and bass clef to establish note names on the lines and spaces of the staff. It also