1. paying back a reciprocal group action
  2. big bucks a large sum of money (especially as pay or profit)
  3. punch bag an inflated ball or bag that is suspended and punched for training in boxing
  4. bearing brass a brass bushing or a lining for a bearing
  5. facing pages two facing pages of a book or other publication
  6. bring back bring back to the point of departure
  7. packing box a large crate in which goods are packed for shipment or storage
  8. black box equipment that records information about the performance of an aircraft during flight
  9. shopping bag a bag made of plastic or strong paper
  10. pinchbeck an alloy of copper and zinc that is used in cheap jewelry to imitate gold
  11. bankbook a record of deposits and withdrawals and interest held by depositors at certain banks
  12. punching bag an inflated ball or bag that is suspended and punched for training in boxing
  13. bouncing Bess plant of European origin having pink or white flowers and leaves yielding a detergent when bruised
  14. think back recapture the past; indulge in memories
  15. sponge bag a waterproof bag for holding bathrooms items (soap and toothpaste etc.) when you are travelling
  16. Pongo pygmaeus large long-armed ape of Borneo and Sumatra having arboreal habits
  17. hang back to lag or linger behind
  18. bunk bed beds built one above the other
  19. book bag a bag in which students carry their books
  20. wingback (American football) the position of the offensive back who lines up behind or outside the end