'bacterian' originates from Modern Latin/Neo-Latin formation based on 'Bacteria', ultimately from Greek 'bakterion' (a diminutive of 'bakteria' meaning 'staff' or 'rod'), with the English adjectival/relational suffix '-an' added.

'bacterian' developed by combining the New Latin/Modern Latin plural/name 'Bacteria' (from Greek 'bakterion' via Latin scientific usage) with the English suffix '-an' to form an adjective/noun meaning 'of or relating to bacteria'; it is parallel to the more common adjective 'bacterial'.

Initially formed to mean 'of or relating to Bacteria' (or 'a member of Bacteria'); over time the intended meaning has largely overlapped with the more common term 'bacterial', and 'bacterian' remains rare or archaic in modern usage.