1 Name for series of items written to be perf. as a group and sometimes linked thematically either musically or by subject, esp. song‐cycle (Ger. Liedercyclus). In opera the greatest cycle (4 operas) is Wagner's Der Ring des Nibelungen.
2 A complete vibration in mus. acoustics.
3 Any of systems of equal temperament in which tonal material is obtained by dividing octave into number of equal intervals.