Definitions of bolster:

• noun:   a pillow that is often put across a bed underneath the regular pillows
• verb:   support and strengthen

  Example: "Bolster morale"

• verb:   prop up with a pillow or bolster
• verb:   add padding to
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #16245)