What is meant by contrary motion in music?

Contrary motion in music refers to the phenomenon where two melodic lines or voices move in opposite directions. For example, if one voice ascends, the other will descend. This interaction creates a harmonic and textural contrast that can enhance the musical experience. Utilizing contrary motion can help maintain independence between voices, thereby enriching the overall sound and providing a sense of balance within the composition.

Understanding contrary motion is also essential for voice leading and counterpoint, as it helps to create a more dynamic and engaging musical line. In contrast, the other choices describe different types of motion that do not accurately represent the concept of contrary motion. For instance, voices moving in the same direction would be considered parallel motion, while voices remaining stable would indicate static movement, and moving all parts at different intervals does not directly relate to the relationship between their directions.