An Etymological Dictionary of the German Language/Polster

by Friedrich Kluge

Polster, m. and n. ‘cushion, bolster,’ from the equiv. MidHG. polster, bolster, OHG. bolstar. m.; corresp. to Du. bolster, AS. and E. bolster, and its equiv. OIc. bólstr. The cognates are connected with the OTeut. root belg, ‘to swell,’ to which Balg also belongs, hence the orig. sense is ‘swelling’ (Teut. bolstra-, from bolhstro-). With the corresponding Sans. root bṛh, ‘to be great.’ Sans. upabarhaṇa, ‘bolster,’ is connected; comp. also Pruss. pobalso, balsinis, ‘pillow,’ Serv. blazina (from *bolzina), ‘pillow.’