IPA: /ˈreɪnˌfɔːl/
KK: /ˈreɪnˌfɔl/
The amount of water that falls from the sky as rain, often measured over a specific period and area.
The rainfall this month has been higher than average, helping to replenish the local rivers.
Rainfall → It is formed from "rain" (from Old English *regn*, meaning water droplets that fall from the sky) and "fall" (from Old English *feallan*, meaning to drop or descend). The word "rainfall" refers to the amount of rain that falls in a specific area over a period of time.
Think of water droplets ('rain') that 'drop' ('fall') from the sky — that's what rainfall means.