Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
in-vulgo (volg-), āvi, ātum, 1, v. a., to bring before the public, to publish, make known: disciplinas acroaticas libris foras editis, Gell. 20, 5, 7; cf. id. 4, 9, 9.
Absol.: quo die Allobroges involgarunt, to give evidence, make a deposition, Cic. Att. 2, 1, 3.
Hence, invulgātus, a, um, P. a., known, common: verba (opp. nova), Gell. 11, 7, 1.