An object in this meaning is the same thing as an objective[?] or task[?]. It comes from old project terminology and refers to the act of actually performing something according to a plan, or rather "according to a project" (the word "project" used to mean "plan").
... a household in the town is $60,209, and the median income for a family is $67,375. Males have a median income of $50,715 versus $34,301 for females. The per capita income ...