progression

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Movement or change from one member of a continuous series to the next.
• noun A continuous series; a sequence: synonym: series.
• noun Mathematics A series of numbers or quantities in which there is always the same relation between each quantity and the one succeeding it.
• noun A succession of tones or chords.
• noun A series of repetitions of a phrase, each in a new position on the scale.

from The Century Dictionary.

• noun In mathematics: A discrete series which has a first element but no last.
• noun The forward change of mutes from one order (surd, sonant, or aspirate) to another, according to Grimm's law.
• noun In Stumpf's psychology, one of the four immanent relations of sensation, the other three being number, similarity, and fusion. It is most clearly illustrated in the facts of sensation intensity.
• noun In gambling, any method of advancing the amount of a lost bet and reducing a bet won: a form of martingale, sometimes called “progress and pinch.” Starting with 5 chips, if the first, bet is lost 6 are wagered; if it is won, 4 only.
• noun A mode of evolution of organisms by increase in size or number of differential additions. It is characteristic of the epacmic phylogeny of most races and is succeeded by retrogression in their acmic or paraemic history.
• noun The act or state of progressing, advancing, or moving forward; a proceeding in a course; advance: as, a slow method of progression.
• noun Lapse or process of time; course; passage.
• noun In mathematics, a series of quantities of which every one intermediate between the first, and the last is a mean of some constant kind between those which immediately precede and follow it.
• noun In philology, the increase or strengthening of a vowel under the accent.
• noun In music: The act, process, or result of advancing from one tone to another (of a particular voice-part), or from one chord to another (of the harmony in general); motion. Progression in either of these senses may be regular or irregular, correct or false. See motion, 14.
• noun Same as sequence.
• noun a series of quantities whose ratios (of each to the preceding) pass through a cycle of n values, as 2, 1, 3, 1½, 4½, 2¼, 6¾, etc. Synonyms Advancement, etc. See progress, n.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of moving forward; a proceeding in a course; motion onward.
• noun Course; passage; lapse or process of time.
• noun (Math.) Regular or proportional advance in increase or decrease of numbers; continued proportion, arithmetical, geometrical, or harmonic.
• noun (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.
• noun 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.
• noun 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.
• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The act of moving from one thing to another.
• noun mathematics A sequence obtained by adding or multiplying each term by a constant.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a movement forward
• noun the act of moving forward (as toward a goal)
• noun a series with a definite pattern of advance