fulcio.

Uncertain. Perhaps related to Proto-Indo-European *bʰelǵʰ- (“to swell”). De Vaan, however, doubts the possibility of a semantic connection between the Latin term, meaning "to support," and the Proto-Indo-European term, meaning "to swell." The root *bʰelg- has been proposed based on a possible connection with Ancient Greek φᾰ́λᾰγξ (phắlănx), Old High German balko, and Icelandic bjálki, although De Vaan rejects such connections. Rix posits, albeit uncertainly, the root *bʰelḱ-, from which a form *bʰl̥ḱ-yé-ti may have emerged, whence fulciō. However, the only other evidence for such a root is Ancient Greek φάλκης (phálkēs), which Beekes considers to be of Pre-Greek origin.