Bolster
WordNet
noun
(1) A pillow that is often put across a bed underneath the regular pillows
verb
(2) Support and strengthen
"Bolster morale"
(3) Add padding to
"Pad the seat of the chair"
(4) Prop up with a pillow or bolster
WiktionaryText
Etymology
Akin to Old Norse ( > Danish bolster), German , .