|1.||[ verb ] carry on the back or shoulders|
"She piggybacked a sick classmate to school"
|2.||[ verb ] (transportation) haul by railroad car|
|3.||[ verb ] (transportation) haul truck trailers loaded with commodities on railroad cars|
|4.||[ verb ] (transportation) ride on someone's shoulders or back|
|5.||[ adverb ] on the back or shoulder or astraddle on the hip|
"she carried her child piggyback"
|6.||[ adverb ] on a railroad flatcar|
"the trailer rode piggyback across the country"
|7.||[ verb ] support on the back and shoulders|
"He piggybacked her child so she could see the show"