[adv] on the back or shoulder or astraddle on the hip; "she carried her child piggyback"
[adv] on a railroad flatcar; "the trailer rode piggyback across the country"
[v] support on the back and shoulders; "He piggybacked her child so she could see the show"
[v] carry on the back or shoulders; "She piggybacked a sick classmate to school"
[v] haul by railroad car
[v] haul truck trailers loaded with commodities on railroad cars
[v] ride on someone's shoulders or back