Here are three words that sound the same way, but all have different meanings.
rain
This is the one you are probably most used to. It is the water that condenses and falls to the earth.
What a beautiful day. It rained a little, and then the sun came out and we saw a rainbow.
rein
Reins are the leather straps that are used to guide a horse when you ride it.
When I was little I used to ride horses very often. One day the horse went crazy and I had to take the reins and really pull him or he would’ve ran straight into the gate.
reign
This is a period of time when a monarch occupies the throne of a country.
The king’s reign over the country was short, but very productive to the country’s economy.