Progression

n.
  1. The act of moving forward; a proceeding in a course; motion onward.
  2. Course; passage; lapse or process of time.
  3. (Math.) Regular or proportional advance in increase or decrease of numbers; continued proportion, arithmetical, geometrical, or harmonic.
  4. (Mus.) A regular succession of tones or chords; the movement of the parts in harmony; the order of the modulations in a piece from key to key.
    5. Arithmetical progression ,
    a progression in which the terms increase or decrease by equal differences, as the numbers {2, 4, 6, 8, 1010, 8, 6, 4, 2} by the difference 2.
    Geometrical progression ,
    a progression in which the terms increase or decrease by equal ratios, as the numbers {2, 4, 8, 16, 32, 6464, 32, 16, 8, 4, 2} by a continual multiplication or division by 2.
    Harmonic progression ,
    a progression in which the terms are the reciprocals of quantities in arithmetical progression, as 1/2, 1/4, 1/6, 1/8, 1/10.