n. & v.
n. 1 a long thick pillow. 2 a pad or support, esp. in a machine. 3 Building a short timber cap over a post to increase the bearing of the beams it supports.
v.tr. (usu. foll. by up) 1 encourage, reinforce (bolstered our morale). 2 support with a bolster; prop up. bolsterer n.
[ OE f. Gmc ]