Noun, pl. adaptations
1. A trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation. (wikipedia.org)
The ability of the eye to adjust to various light intensities by regulating the pupil of the quantity of light entering the eye. (biology-online.org)
a. The proper fitting of a denture.
b. The degree of proximity and interlocking of restorative material to a tooth preparation.
c. The exact adjustment of bands to teeth. (biology-online.org)
Word origin: From French adaptation, from Medieval Latin adaptatio, from Latin adaptare