'atmometer' originates from Greek elements, specifically 'atmos' (Greek) meaning 'vapor' and 'metron' (Greek) meaning 'measure', combined in modern scientific coinage to form the name of the instrument.

'atmometer' was formed in scientific English (19th century onward) by combining the prefix 'atmo-' (from Greek 'atmos') with the suffix '-meter' (from Greek 'metron'), creating a compound meaning 'vapor-measurer' that entered modern usage without major intermediate forms.

Initially coined to denote an instrument that measures atmospheric vapor or evaporation, the meaning has remained essentially the same and is still used for devices that estimate evaporation or evapotranspiration.