Emily Dickinson Lexicon

BOL'STER, n. [Sax. bolster; Sw. bolster; Ger. polster; Dan. bolster-dyne, a feather bed; Pers. بَالِشتْ balisht. In Dutch, bolster is a husk, cod, or shell.]

1. A long pillow or cushion, used to support the head of persons lying on a bed; generally laid under the pillows.
2. A pad, or quilt, used to hinder pressure, support any part is of the body, or make a bandage sit easy upon a wounded part; a compress.
3. In saddlery, a part of a saddle raised upon the bows or hinder part, to hold the rider's thigh. – Farrier's Dict.
4. In ships, a cushion or bag, filled with tarred canvas, used to preserve the stays from being worn or chafed by the masts. – Mar. Dict.