'bacteriostat' originates from the combining form 'bacterio-' (from New Latin 'bacterium', ultimately from Greek 'bakterion' meaning 'small staff' or 'rod') plus the suffix '-stat' (from Greek elements related to 'stasis'/'statos', meaning 'to stop' or 'to stand still').

'bacteriostat' was formed in modern scientific/medical English by combining the New Latin/Greek-derived element 'bacterio-' with the suffix '-stat' used in scientific coinages (similar to 'hemostat', 'thermostat'), and entered technical usage in the 20th century.

Initially and throughout its usage it has meant 'an agent that stops or inhibits bacterial growth'; this technical meaning has been stable over time.