The word 'rain' functions as both a noun and a verb. Examples:
As a noun: The rain made large puddles in the road.
As a verb: It will rain today so please remember your umbrella.
The rain storm did not deter me from going shopping.
Although it was cloudy, he was uncertain that it would rain.
If you want to know how to use it: "Sorry, I'll take a rain check. Maybe next time." Like that.
Here is an example sentence with the word 'rain':Rain splattered down as if the sky itself was weeping with grief.
The researcher studied animal behavior in the Mayan rain forest. Roscoe's hired a new trends researcher.
It began to rain when the thunderstorm approached.
He was drenched by the pouring rain.
I suspect that it is possible that it will rain soon.
We will decamp before the rain begins.
a big scud of rain will fall
The heavy rain is eroding the soil.
The rain dampened our plans for an outdoor picnic.
The rain was intermittent this weekend, then it went away.
The rain storm did not deter me from going shopping.
the cat was outside in the rain, crying piteously
Although it was cloudy, he was uncertain that it would rain.
The flames will smolder for hours if it doesn't rain soon.