1. buckbean perennial plant of Europe and America having racemes of white or purplish flowers and intensely bitter trifoliate leaves; often rooting at water margin and spreading across the surface
  2. backspin spin that retards or reverses the forward motion
  3. backbone the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
  4. backpack a bag carried by a strap on your back or shoulder
  5. back pack a bag carried by a strap on your back or shoulder
  6. backup man someone who takes the place of another
  7. black pine tall symmetrical pine of western North America having long blue-green needles in bunches of 3 and elongated cones on spreading somewhat pendulous branches; sometimes classified as a variety of ponderosa pine
  8. bogbean perennial plant of Europe and America having racemes of white or purplish flowers and intensely bitter trifoliate leaves; often rooting at water margin and spreading across the surface
  9. backband a broad band that passes over the back of a horse and supports the shafts of a vehicle
  10. back down move backwards from a certain position
  11. backup the act of providing approval and support
  12. jack pine slender medium-sized two-needled pine of eastern North America; with yellow-green needles and scaly grey to red-brown fissured bark
  13. black bean black-seeded bean of South America; usually dried
  14. backbeat a loud steady beat
  15. backdown a retraction of a previously held position
  16. pigpen a pen for swine
  17. packman someone who travels about selling his wares
  18. bugbane North American plant having large leaves and yellowish green flowers growing in racemes; yields a toxic alkaloid used medicinally
  19. duckpin a bowling pin that is short and squat by comparison with a tenpin
  20. papain a proteolytic enzyme obtained from the unripe papaya