Added 9 October 2026 radiometer noun Categories: ThingsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about radiometer at Wordnik → Where our words come from → Meter to detect and measure radiant energy (electromagnetic or acoustic). Origin From radio- + -meter. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: microwaveirradiometerroentgenometerradiomicrometerphotoradiometerradiographreflectometerspectroradiometerriometertelespectroradiometerabsorptiometerpyrheliometer Back to today's word