increment

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

• noun The process of increasing in number, size, quantity, or extent.
• noun Something added or gained.
• noun A slight, often barely perceptible augmentation.
• noun One of a series of regular additions or contributions.
• noun Mathematics A small positive or negative change in the value of a variable.

from The Century Dictionary.

• noun In forestry, the volume or value of wood produced during a given period by the growth of a tree or of a stand. See accretion, 5.
• noun A uniform variation; a regular increase.
• noun The act or process of increasing; a growing or swelling in bulk, quantity, number, value, or amount; augmentation.
• noun Something added; an increase or augmentation; specifically, in mathematics, the excess (positive or negative) of the value which a function would have if its independent variable were increased by any amount, especially by unity, over the value which it has for any particular value of the variable; the difference of a function; also, an arbitrary supposed increase of an independent variable.
• noun In rhetoric, a species of amplification which consists in magnifying the importance of a subject (person or thing) by stating or implying that it has no superior, or that the greatest of all others is inferior to it: as, Thou hast slain thy mother. What more can I say? Thou hast slain thy mother.
• noun In Latin grammar, a syllable in another form of a word additional to the number of syllables in the nominative singular of a noun, adjective, etc., or the second person singular of the present indicative active of a verb.
• noun In heraldry, the state of the moon when crescent: as, the moon in her increment.

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

• noun The act or process of increasing; growth in bulk, guantity, number, value, or amount; augmentation; enlargement.
• noun Matter added; increase; produce; production; -- opposed to decrement.
• noun (Math.) The increase of a variable quantity or fraction from its present value to its next ascending value; the finite quantity, generally variable, by which a variable quantity is increased.
• noun (Rhet.) An amplification without strict climax
• noun (Math.) an infinitesimally small variation considered in Differential Calculus. See Calculus.
• noun (Math.) a calculus founded on the properties of the successive values of variable quantities and their differences or increments. It differs from the method of fluxions in treating these differences as finite, instead of infinitely small, and is equivalent to the calculus of finite differences.

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

• noun The action of increasing or becoming greater.
• noun heraldry The waxing of the moon.
• noun The amount of increase.
• verb intransitive, transitive To increase by steps or by a step, especially by one.

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

• noun the amount by which something increases
• noun a process of becoming larger or longer or more numerous or more important