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báculo m. (Noun) "staff"
16th cent. borrowing from Latin baculum 'id.' Of unknown origin. Borrowed from a non-Indo-European language with a root *bak(k)- "stick," "staff."
Portuguese báculo, Galician báculo, French bâcle, Italian bacolo
Old Irish bacc "crooked staff," "hook" (< *bakko-), Old Welsh bach "hook," Old Breton bah 'id.,' Old Cornish bagh 'id.'
Middle Dutch pegel "peg," Old English pægel "wine jug"
Lithuanian bàkstelėti? "to thrust," Latvian bakstît? "to poke"
Ancient Greek βάκτρον (báktron) "stick" (< *bak-tro-), βακτηρία (baktería) "staff," "scepter" (< *bak-tér-)
Basque makila "walking stick," probably from Latin bacila "sticks," plural of baculum

"A more widely distributed (West Central) root for 'club' is *bak- (e.g. OIr bacc 'staff', Lat baculum 'staff', Grk báktron 'staff'; a Middle Dutch cognate pegge suplies NE peg); the initial b- has been explained either as the mark of a 'popular word' (i.e. one apparently used only in informal contexts and subject to the possibility of special phonological changes) or a loanword from some non-Indo-European language." ~ Mallory & Adams, The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World (2006)