Final answer:
A sequence is the restatement of a musical idea at a higher or lower pitch, distinct from a theme, motive, or ostinato.
Step-by-step explanation:
The restatement of a musical idea at a higher or lower pitch is called a sequence. This term describes the repetition of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice. It is different from a theme, which is the main melody, a motive, which is a short musical idea, or an ostinato, which is a repeated musical pattern. For example, in an orchestra, if a sequence of notes played by the woodwind instruments at a high frequency is subsequently mirrored by the stringed instruments at a lower frequency, this would be considered a sequence. Similarly, a sequence in a film score can amplify the mood and tension on the screen, as with the example of sorrowful music played at varying pitches during a scene.