mid-15c., from Medieval Latin habituationem, noun of action from habituare (see habituate (v.)).
habituation ha·bit·u·a·tion (hə-bĭch'ōō-ā'shən)
n.
The process of habituating or the state of being habituated.
Physiological tolerance to a drug resulting from repeated use.
Psychological dependence on a drug.
The decline of a conditioned response following repeated exposure to the conditioned stimulus.