·noun Course; passage; lapse or process of time.
II. Progression ·noun The act of moving forward; a proceeding in a course; motion onward.
III. Progression ·noun Regular or proportional advance in increase or decrease of numbers; continued proportion, arithmetical, geometrical, or harmonic.
IV. Progression ·noun 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.