I. ̷ ̷ˌ ̷ ̷ ̷ ̷ˈwāshən noun
( -s )
Etymology: Middle English habituacioun, from Medieval Latin habituation-, habituatio, from Late Latin habituatus + Latin -ion-, -io -ion
1. : the act or process of making habitual or accustomed
the essence of the tragedy of Macbeth — the habituation to crime — T.S.Eliot
2.
a. : tolerance to the effects of a drug acquired through continued use and manifested by decreasing effectiveness of the same amount of drug administered in successive doses
cathartic habituation
narcotic habituation
b. : the psychic or emotional counterpart of acquired tolerance that is manifested by psychologic dependence upon a drug after a period of use — often distinguished from addiction
II. noun
: decrease in responsiveness upon repeated exposure to a stimulus