baculum.

Uncertain, though probably loaned from a non-Indo-European substrate. The term is possibly cognate with Proto-Slavic *bokъ, Proto-Celtic *bakkos, Ancient Greek βάκτρον (báktron), and Proto-West Germanic *pagil. Based on these forms, the Proto-Indo-European root *bak- has been reconstructed. The term could be construed as a derivative of Proto-Indo-European *bak-tlom, although De Vaan postulates a pre-form *bak-k(e)los. The linguist Gert Klingenschmitt has proposed an alternative reconstruction *gʷaḱ-, though the linguist Thomas Olander suggests that a form *gʷh₂ḱ- could also yield the expected forms according to this theory. Nevertheless, such an alternative reconstruction would perhaps require the Latin term to have been borrowed from an Osco-Umbrian language, though it would allow for Old Armenian կալ (kal, “threshing floor”) to be adduced as a cognate. See also beccus, Ancient Greek βακτηρία (baktēría).