progression

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The process of progressing; progress.
2. n. Movement from one member of a continuous series to the next.
3. n. A continuous series; a sequence. See Synonyms at series.
4. n. Mathematics A series of numbers or quantities in which there is always the same relation between each quantity and the one succeeding it.
5. n. Music A succession of tones or chords.
6. n. Music A series of repetitions of a phrase, each in a new position on the scale.

Century Dictionary and Cyclopedia

1. n. The act or state of progressing, advancing, or moving forward; a proceeding in a course; advance: as, a slow method of progression.
2. n. Lapse or process of time; course; passage.
3. n. 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. Arithmetical, geometrical, harmonic, arithmetico-geometrical, and quadratic progressions are progressions depending on means so named.
4. n. In philology, the increase or strengthening of a vowel under the accent.
5. n. 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.
6. n. Same as sequence.
7. n. 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.
8. n. In mathematics: A discrete series which has a first element but no last.
9. n. The forward change of mutes from one order (surd, sonant, or aspirate) to another, according to Grimm's law.
10. n. 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.
11. n. 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.
12. n. 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.

Wiktionary

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

GNU Webster's 1913

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

WordNet 3.0

1. n. a movement forward
2. n. the act of moving forward (as toward a goal)
3. n. a series with a definite pattern of advance