1580s, "to act as a patron towards, favor, assist," from patron + -ize, or from Old French patroniser. Meaning "treat in a condescending way" is attested by 1797; the sense of "give regular business to" is from 1801. Related: Patronized; patronizing; patronization.
We patronize this store
patrolman
patron
patronage
patroness
patronise
patronize
patronizing
patronym
patronymic
patroon
patsy