augur.

According to De Vaan, Proto-Italic *augos ~ *augezos n, from Proto-Indo-European *h₂éwgos; compare Sanskrit ओजस् (ojas, “strength, vigor”), Avestan 𐬀𐬊𐬘𐬀𐬵 (aojah), 𐬀𐬊𐬔𐬀𐬵 (aogah, “might, power”) as well as Latin augeō (“to increase”), augustus (< *augos-tos). The noun *augos would have developed from "reinforcement" to "(one) who makes grow". However, it is not clear why the term is not inflected like other neuter s-stems. The expected declension pattern, if the aforementioned theory is accepted, would be *augus ~ *augeris. The term might have leveled the e/o-variation in the suffix, yielding *augos ~ *augoris. There is attestation of a similar development in fulgur ~ fulguris, though there is attestation for the unassimilated stem fulgor-, whereas there is no evidence for augor-. It is also unclear how a neuter verbal abstract become a masculine noun denoting the role of a religious official. There are few other parallels for original neuter s-stems coming to refer to animate entities, and all of them are either doubtful or have special explanations. For instance, Venus f reflects Proto-Indo-European *wénh₁-os ~ *wénh₁-es-os, though it specifically refers to a goddess who functioned as the personification of love, and its case is therefore not an exact match for the situation of augus.