The interval between two quantities plotted along an axis where the second quantity is ten times the first. A frequency ratio or interval of 10:1, as opposed to an octave, which is a 2:1 ratio. Sometimes the rolloff of a filter or equalizer is expressed in dB/decade, rather than in dB/octave. A rolloff of 20dB/decade is equal to A rolloff of 6dB/octave. The decade interval has no musical significance, but is used in the discussion of logarithmic quantities such as decibels.