bolster bolster /ˈboʊlstɝ/

noun

1. () A pillow that is often put across a bed underneath the regular pillows  ( long pillow , bolster )
   a pillow that is often put across a bed underneath the regular pillows
    She placed a bolster behind her back for extra support while reading.
   She placed a bolster behind her back for extra support while reading.
   
   

verb

1. () Support and strengthen  ( bolster up , bolster )
   support and strengthen
    Bolster morale
   bolster morale
   
2. Add padding to  ( bolster , pad )
   add padding to
    Pad the seat of the chair
   pad the seat of the chair
   
3. Prop up with a pillow or bolster  ( bolster )
   prop up with a pillow or bolster