1. Evolutionary. Some property of an organism caused by natural selection acting on the genotype, improving the fitness of an organism. This is a long term process.
2. Physiological. A physiological change in an organism, resulting from exposure to certain environmental conditions, allowing it to respond more effectively to them (e.g., tanning of the skin in sunshine).
3. Sensory. A short term change in excitability of a sense organ through continuous stimulation.

Alternative forms for adaptation : adaptations, adapted.