noun

• (uncountable) The process of adapting something or becoming adapted to a situation; adjustment, modification.
• (countable) A change that is made or undergone to suit a condition or environment.
• (uncountable, evolutionary theory) The process of change that an organism undergoes to be better suited to its environment.
• (countable, evolutionary theory) An instance of an organism undergoing change, or the structure or behavior that is changed.
• (uncountable) The process of adapting an artistic work from a different medium.
• (countable, authorship) An artistic work that has been adapted from a different medium.
• (sociology) The means by which social groups adapt to different social and physical environments.