What is rain?

The word "rain" has two interpretations.

The first is the solar terms. Rain, the second of the twenty-four solar terms, is located on the fifteenth day of the first month of each year (February 18-20 in Gregorian calendar), and the sun reaches 330 degrees of the yellow meridian. Rain, like Grain Rain, light snow and heavy snow, is a solar term reflecting precipitation;

The second is rain clouds and precipitation in the rainy season. Rain clouds, precipitation and rain are water vapor evaporated from the earth and condensed when it meets cold at high altitude (commonly known as clouds). When the water content of the condensed water vapor mass is too high and the updraft "can't hold", it will fall to the ground in the form of water droplets, which is rain.