English
humidex
Blend of humidity + index.
Proto-Italic *ūmo- ‘wet’
…
Latin hūmidus
Medieval Latin hūmiditās
Old French humidité ‘moistness’
Middle English humidite
English humidity
Proto-Indo-European *deyḱ- ‘to point out’
Proto-Indo-European *déyḱeti ‘to be pointing out’
Proto-Italic *deikō ‘to show’
Latin dīcō ‘to say, indicate’
Latin index ‘discoverer, informer; forefinger’
English index
Today it means
noun A measurement used by Canadian meteorologists to reflect the combined effect of heat and humidity, as the apparent temperature felt by a person.
Language periods are conventional ranges, not dates for this word.
Etymograph / humidex