The story
- Latin · derived fromūmidus“damp, moist, wet”
- Medieval Latin · derived fromhūmiditās
- Old French · derived fromhumidité
- Middle English · inherited fromhumidite
- English todayhumidity
From Middle English humidite, borrowed from Old French humidité, from Medieval Latin hūmiditās, from Latin ūmidus (“damp, moist, wet”). By surface analysis, humid + -ity.
Etymology from Wiktionary, CC BY-SA 4.0.