'aquameter' originates from Latin and Greek-derived elements: Latin 'aqua' meaning 'water' and the combining form '-meter' (from Greek 'metron') meaning 'measure'.

'aquameter' was formed in English by combining the prefix 'aqua-' (Latin) with the suffix '-meter' (from Greek 'metron', via Latin and French forms) in the 19th century, modeled on other instrument names such as 'thermometer' and 'speedometer'.

Initially it meant 'an instrument for measuring water (volume or flow)',' and that core meaning has remained largely unchanged in modern usage.