Some words exist in English language which have same sounds but different meanings. Rain, reign and rein also fall in this category. These three words have almost similar pronunciations but their meanings and usage is totally different. Here are few examples to make you understand the difference between these homophones.
Rain as noun:
When the moisture of our atmosphere is gathered up in the sky, it goes through the process of condensation (conversion of vapors to liquid) and fall as separate water droplets. These water drops are known as rain which is the showering of water from the sky on earth. Rain is a natural phenomenon that everyone is aware of and is a common noun.
Rain is also used for describing a large quantity of things that are descending or that fall upon something. This rain has synonyms like shower, deluge, flood, torrent, spate, and avalanche, outpouring, rush or flurry. When there is a heavy fall of something, it is called rain.
Rain as verb:
The falling of water drops from the sky is rain as verb which describes the action taking place. It started raining. The rain when used as a verb, defines the act of water falling or a descend of anything. In other words, the meaning of rain is same as a noun and a verb, the difference lies is the usage only.
Reign as verb:
Reign is also used to describe the best or most important thing in a particular area or domain. Baseball reigns the supreme in America. The dominant feature of a situation or place is also called reign.
Reign as noun:
Reign is used to describe the ruling period of a monarch. The reign of Henry VIII was 56 years. The predominant or preeminent time of something which was most important in that time period is also called its reign. When some quality, feature or characteristic is most influential in a particular time, that is its reign.
Rein as noun:
A long, narrow strap attached at one end to a horse's bit, which is used in pairs to guide or check a horse while riding or driving is known as rein. The reins of a horse are used by riders to direct the horse and get firm support while riding.
Rein as verb:
Rein has similar meaning when used as a noun or a verb. When a horse’s reins are pulled to check or guide, the action known as rein. Or when something or someone is kept under control or is restrained, the action is again called rein.
Rain, reign or rein:
When water falls down from the sky, rain washes the earth, when a ruler dies, his reign is over and when a rider rides a horse, he straightens its reins. So next time you write something, make sure you know which of these homophones to use.