This document provides definitions and explanations of various musical terms that will be covered on an upcoming music appreciation midterm exam. It defines key concepts like interval, pitch, tone, frequency, texture, dynamics, and musical forms like monophony, homophony, polyphony, imitative polyphony, chorale, strophic form, motet, psalm tune, opera, aria, oratorio, cantata, and canon. It also briefly mentions Hildegard of Bingen and identifies the four main elements of music.