<p><strong>Noun</strong></p><ul><li>A tone on the eighth degree from a given tone.</li><li>The interval encompassed by such tones.</li><li>The harmonic combination of such tones.</li><li>A series of tones, or of keys of an instrument, extending through this interval.</li><li>A pipe-organ stop whose pipes give tones an octave above the normal pitch of the keys used.</li><li>A series or group of eight.</li><li>A group of eight lines of verse, especially the first eight lines of a sonnet in the Italian form.</li><li>The eighth day from a feast day, counting the feast day as the first.</li><li>The period of eight days beginning with a feast day.</li></ul><p><strong>Adjective</strong></p><ul><li>Pitched an octave higher.</li></ul>