'bacula' originates from Latin, specifically the word 'baculum', where 'baculum' meant 'stick' or 'staff'.

'baculum' entered scientific and descriptive English usage largely unchanged from Latin; the Latin plural 'bacula' is used in English zoological contexts as the plural of 'baculum'.

Initially, it meant 'stick' or 'staff' in Latin; over time the term was specialized in biological contexts to refer specifically to the penile bone ('os penis') while the original general sense of 'stick' remains in historical or descriptive uses.