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octāvus, a, um, adj. [octo], 
- I. the eighth: octava pars, Cic. Att. 15, 26, 4: legio, Caes. B. G. 2, 23: marmor, the eighth mile-stone, Mart. 9, 65, 4.
 
- II.  Subst.: octāva, ae, f. 
 
- A.  (Sc. hora.) The eighth hour of the day, Mart. 4, 8, 5; Juv. 1, 49.
 
- B.  (Sc. pars.) The eighth part, as a tax, Cod. Just. 4, 65, 7; Cod. Th. 4, 12, 6; Ulp. Fragm. 6, 12 (cf. octavarius).
 
- III.  Adv.: octāvum, for the eighth time, Liv. 6, 36, 7.