galgulus
From LSJ
τούτου δὲ συμβαίνοντος ἀναγκαῖον γίγνεσθαι πάροδον καὶ τροπὰς τῶν ἐνδεδεμένων ἄστρων → but if this were so, there would have to be passings and turnings of the fixed stars
galgŭlus: i, m.,
I a small bird, the witwall, Plin. 30, 11, 28, § 94 Jan. (al. galbula).
