Lewis & Short

2. Lăbĕo, ōnis, m., a surname: labra, a quibus Brocchi Labeones dicti, Plin. 11, 37, 60, § 159.
Esp. a surname of the Antistii, Atinii, Fabii, and other Roman families; so, Antistius Labeo, a celebrated teacher of law in the time of Augustus, Gell. 13, 10, 1; Dig. 1, 2, 2, § 44; 47; Gai. Inst. 1, 188.