Lewis & Short

Almo, ōnis, m., a small stream, almost entirely dry in summer, on the south side of Rome, which, crossing the Via Appia and Via Ostiensis, flows into the Tiber (now the Aquataccia). In it the priests of Cybele annually washed the image and sacred implements of the temple of that goddess; v. Ov. F. 4, 337; 6, 340; Mart. 3, 47; Luc. 1, 600; cf. Mann. Ital. 1, 588; Müll. Roms Campagn. 2, 400 sq.
As a river-god, father of the nymph Lara, Ov. F. 2, 601.