'baculite' originates from New Latin/Greek, specifically the genus name 'Baculites', where Latin 'baculum' meant 'rod' and the Greek-derived suffix '-ites' was used in fossil/mineral names (roughly 'stone' or 'connected with').

'baculite' changed from the scientific genus name 'Baculites' (established in the 19th century as a taxonomic name) and was adopted in English as the common noun 'baculite' to refer to fossils of that genus.

Initially, the name referred specifically to the taxonomic genus 'Baculites' (a 'rod-like' shell), but over time it has been used in English to mean 'a fossil of that straight-shelled ammonite'.