Definitions:

1. bring into alignment with verb
   • an amendment to piggyback the current law
2. on a railroad flatcar adverb
   • the trailer rode piggyback across the country
3. on the back or shoulder or astraddle on the hip adverb
   • They carried their child piggyback.
4. support on the back and shoulders verb
   • They piggybacked their child so the child could see the show.

Synonyms:

• pickaback
• pig-a-back