noun, masculine/ˈfuste/plural: fustes
wood; stick; shaft of a spear; stem of a leaf; foundation or basis
Inherited from Latin fūstis (“stick, club”). Noting the unexpected /f-/, Coromines & Pascual dismiss the possibility of a borrowing from neighbouring Romance varieties (cf. Galician fuste) and point out that the word was common in medieval times but restricted to more technical registers afterwards, which may have allowed the traditional orthography with ⟨f⟩ to determine the pronunciation.