volucer.

From volō, volāre (“to fly”). The masculine nominative singular form is derived by syncope from pre-Latin *wolukris, which probably developed by dissimilation from earlier *woluklis or *weluklis, with a suffix ultimately derived from pre-Proto-Italic *-tlis, *-tl-, a variant of the zero-grade of Proto-Indo-European *-tḗr (suffix forming agent nouns), related to Latin -tor. Compare alacer and alacris. However, De Vaan regards the origin of the *-kris ending as uncertain. Although the stem of the verb volō (“to fly”) is volā-, this adjective is built on a stem volu- with a short /u/, which De Vaan considers unexplained. Sen argues that the stem *welu- was taken from volucra (“larva of a moth that infests vines”), a derivative of volvō (“to (cause to) roll”), based on semantic and formal similarity. There is no consensus on the ultimate etymology of volō (“to fly”), but one hypothesis is that it comes from Proto-Indo-European *gʷelH- (“to throw”); assuming this initial *gʷ- is correct, Weiss 2009 reconstructs an earlier stage as *gʷolu-tlis, comparing it to Sanskrit गरुड (garuḍá) (which Weiss derives from earlier *garutráḥ), and Schrijver compares it to Sanskrit गरुत्मान् (garutmān).