1a forked bone (the furcula) between the neck and breast of a bird. According to a popular custom, this bone from a cooked bird is broken by two people and the holder of the longer portion is then entitled to make a wish.
2a forked element in the suspension of a motor vehicle or aircraft, typically attached to a wheel at one end with the two arms hinged to the chassis: [as modifier]:double wishbone suspension
3 Sailing a boom in two halves which curve outwards around a sail and meet aft of it.
wishbone in other Oxford dictionaries
Definition of wishbone in the US English dictionary