- On the shoulders or back: ride piggyback; a piggyback ride.
- By or relating to a method of transportation in which truck trailers are carried on trains, or cars on specially designed trucks.
- In connection with something larger or more important: a tariff provision that came piggyback with the tax bill; a piggyback provision to a new piece of legislation.
- The act of transporting piggyback.
- To cause to be aligned with an issue, for example, that is larger or more important: "a $21.5-million federal grant to piggyback city and state subsidies” ( New York).
- To function as if carried on the back of another: "This reagent will piggyback onto an enzyme” ( Seth Rolbein).