mid-15c., "action of forming a habit; customary practice," from Medieval Latin habituationem (nominative habituatio), noun of action from past participle stem of Late Latin habituare "to bring into a condition or habit of the body," from Latin habitus "condition, appearance, dress," originally past participle of habere "to have, hold, possess; wear; find oneself, be situated; consider, think, reason, have in mind; manage, keep," from PIE root *ghabh- "to give or receive." Meaning "condition of being habituated" is from 1816.