ad·ap·ta·tion (ădˌăp-tāˈshən)

1. The acquisition of modifications in an organism that enable it to adjust to life in a new environment.
2. An advantageous change in the function or constitution of an organ or tissue to meet new physiological conditions.
3. Adjustment of the pupil and retina to varying degrees of illumination.
4. A property of certain receptors through which they become less responsive or cease to respond to repeated or continued stimuli of constant intensity.
5. The fitting, condensing, or contouring of a restorative dental material to a tooth or cast.
6. The dynamic process in which the behavior and physiological mechanisms of an individual continually change to adjust to variations in living conditions.