Etymology of the French word acostumer
the Old French word acostumer
derived from the Old French word costume
derived from the Italian word costume
derived from the Classical Latin word consuetudo (experience; empirical knowledge; sexual; habit, custom, usage)
derived from the Latin word consuetus (accustomed. used; customary, habitual)
derived from the Latin word consuescere (accustom oneself; become, be accustomed; be intimate, have sexual intercourse with; form a habit)
using the Latin prefix con- (together)
derived from the Latin word suescere (become accustomed)