"Piggyback" means to carry or ride on someone's back, especially when they are already carrying something or someone else. It is like getting a free ride by hitching a ride on someone else. Full definition
As a PadFone, the Asus PadFone S is a 9 - inch tablet with a 5 - inch smartphone riding piggyback on it. (tabletmonkeys.com)
Owner financing is a type of piggyback loan in which the second mortgage portion is carried by the home seller. (themortgagereports.com)
This mechanic does not make you feel like a mercenary leader; it makes you feel like a secretary at a back - alley loan shark piggybacking off the neighbour's WIFI. (invisioncommunity.co.uk)