Mid 16th century; earliest use found in Miles Coverdale (1488–1569), Bible translator and bishop of Exeter. Either from accustom + -ary, or alteration of customary after accustom.
Definition of accustomary in US English:
accustomary
adjectiveəˈkʌstəm(ə)ri
Usual, customary.
Origin
Mid 16th century; earliest use found in Miles Coverdale (1488–1569), Bible translator and bishop of Exeter. Either from accustom + -ary, or alteration of customary after accustom.