a card or ticket entitling the holder to purchase two tickets to a theatrical performance at a reduced price.
a coupon or offer entitling a person to purchase two items or services for approximately the price of one.
a person who belongs to two minority groups and can satisfy two quotas or appeal to two political constituencies, especially a black woman, who can be counted twice in a position she holds, as fulfilling a racial and a sexual quota.
from the phrase two for
(the price of one, a nickel,
etc.), with final (ər) humorously taken as -er1
; cf. gofer