adaptation

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The act or process of adapting.
2. n. The state of being adapted.
3. n. Something, such as a device or mechanism, that is changed or changes so as to become suitable to a new or special application or situation.
4. n. A composition that has been recast into a new form: The play is an adaptation of a short novel.
5. n. Biology An alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relationship to its environment.
6. n. Physiology The responsive adjustment of a sense organ, such as the eye, to varying conditions, such as light intensity.
7. n. Change in behavior of a person or group in response to new or modified surroundings.

Century Dictionary and Cyclopedia

1. n. The act of adapting or adjusting; the state of being adapted or fitted; adjustment to circumstances or relations.
2. n. That which is adapted; the result of altering for a different use. Specifically, a play translated or constructed from a foreign language or a novel, and rendered suitable for representation: as, this comedy is a free adaptation from a French author.
3. n. In biology, advantageous variation in animals or plants under changed conditions; the result of adaptability to, and variability under, external conditions; the operation of external influences upon a variable organism, or a character acquired by the organism as the result of such operation. It is regarded as one of two principal factors in the evolution of organic forms, inducing those changes which it is the tendency of the opposite factor, heredity, to counteract, the result in any given case being the balance between adaptation and heredity, or the diagonal of the parallelogram of forces which adaptation and heredity may be respectively considered to represent.
4. n. Same as immunization.

Wiktionary

1. n. uncountable The quality of being adapted; adaption; adjustment.
2. n. uncountable Adjustment to extant conditions: as, adjustment of a sense organ to the intensity or quality of stimulation; modification of some thing or its parts that makes it more fit for existence under the conditions of its current environment.
3. n. countable Something which has been adapted; variation.

GNU Webster's 1913

1. n. The act or process of adapting, or fitting; or the state of being adapted or fitted; fitness.
2. n. The result of adapting; an adapted form.

WordNet 3.0

1. n. (physiology) the responsive adjustment of a sense organ (as the eye) to varying conditions (as of light)
2. n. the process of adapting to something (such as environmental conditions)
3. n. a written work (as a novel) that has been recast in a new form