B0376600 (bōl′stər)n. A long narrow pillow or cushion.tr.v.bol·stered, bol·ster·ing, bol·sters1. To support or prop up with or as if with a long narrow pillow or cushion.2. To buoy up or hearten: Visitors bolstered the patient's morale.[Middle English, from Old English; see bhelgh- in Indo-European roots.]bol′ster·er n.EncyclopediaSeebolster