the.com/rainfall

means The amount of rain that falls in a given place over a given time, usually measured in inches or millimeters.

from A straightforward compound of 'rain' and 'fall' — the Old English 'regn' meeting 'feallan,' both sturdy Germanic words that have been doing their jobs for over a thousand years. The combined noun itself is younger, emerging as a plain descriptive term once people needed a tidy word for 'how much rain fell,' especially for farming, weather records, and the quiet human habit of measuring the sky.