sustre
Sus"ter, Sus"tre, n.; pl. Susters (, Sustres, or Sustren (. Defn: Sister. [Obs.] Chaucer. There are seven sustren, that serve truth ever. Piers Plowman.
Sus"ter, Sus"tre, n.; pl. Susters (, Sustres, or Sustren (. Defn: Sister. [Obs.] Chaucer. There are seven sustren, that serve truth ever. Piers Plowman.