sīrus, i, m., = σιρός,
a pit to keep corn in, an underground granary (cf. cumera), Plin. 18, 30, 73, § 306; Col. 1, 6, 15; Curt. 7, 4, 24; cf. Auct. B. Afr. 65; Vitr. 6, 8 ( Varr. R. R. 1, 57 and 63, written as Greek).
sīrus ī, m , σειρός, a pit for storing grain, underground granary, Cu. ...
An Elementary Latin Dictionary