- a long, often cylindrical, cushion orpillow for a bed, sofa, etc.
- anything resembling this in form or inuse as a support.
- any pillow, cushion, or pad.
O.E. bolster "bolster, cushion, something stuffed so that it swells up," especially "long, stuffed pillow," from P.Gmc. *bolkhstraz (cf. O.N. bolstr, Dan., Swed., Du. bolster, Ger. polster), from PIE *bhelgh- "to swell" (see belly). The verb in the figurative sense is from c.1500, on the notion of "to support with a bolster, prop up." (http://dictionary.reference.com/browse/bolster)
"On the Great Barrier Reef, the sea cucumbers are the size of bolster cushions."
- Elizabeth Kolbert, The Sixth Extinction: an Unnatural History