In music, a blind octave is the alternate doubling above and below a successive scale or trill notes: "the passage being played...alternately in the higher and lower octave." [1] According to Grove's Dictionary of Music and Musicians, the device is not to be introduced into the works of "older composers" (presumably those preceding Liszt). [2]
Alternately, a blind octave may occur "in a rapid octave passage when one note of each alternate octave is omitted." [3] The effect is to simulate octave doubling using a solo instrument.