Lewis & Short

sŏrōrĭus, a, um, adj. [soror].

  1. I. In gen., of or belonging to a sister, sisterly: cena, made because a sister was found, Plaut. Curc. 5, 2, 60: stupra, with a sister, Cic. Sest. 7, 16: moenia, i. e. of Dido, Ov. F. 3, 559: oscula, as a sister gives to a brother, sisterly, id. M. 4, 334; 9, 539.
  2. II. In partic.: Sororium Tigillum, the Sister’s beam, a place in Rome sacred to Juno, where Horatius was obliged to creep under a beam laid across the way as a punishment for having killed his sister, Liv. 1, 26, 13; Aur. Vict. Vir. Ill. 4; Fest. pp. 297 and 307 Müll.