- Rain is the drops of water that fall from clouds.
- Reign is the period during which a sovereign occupies the throne.
- Rein is a long strap used to lead a horse.
RainThe noun rain denotes the drops of water that fall from the clouds. (The word rain can also be used as a verb.)
- A crown is merely a hat that lets the rain in. (Frederick the Great)
- My face looks like a wedding cake left out in the rain. (W H Auden)
- If it were raining soup, they would go out with forks. (Brendan Behan) (This is an example of rain being used as a verb.)
ReignThe noun reign means the period during which a sovereign occupies the throne. (The word reign can also be used as a verb.)
- Queen Elizabeth II has launched 17 ships during her reign.
- Over the course of the Queen's reign, over a million people have attended garden parties at Buckingham Palace.
- Queen Victoria reigned for 63 years. (This is an example of reign being used as a verb.)
ReinThe noun rein denotes a long strap, usually made from leather, that is used to lead a horse. (The word rein can also be used as a verb.)
- If passion drives you, let reason hold the reins. (Benjamin Franklin)
- Reins can be made of leather, nylon, or metal.
- At what point does CNN wise up and rein in 'Larry King Live' to save itself? (Phil Rosenthal) (This is an example of rein being used as a verb.)
Having free rein to do something means you have considerable freedom to act as you please. The term derives from the idea of loosening a horse's reins to give it more freedom.
Even though free rein is the original version of this saying, the term free reign has been so widely misused in its place, it has developed into an acceptable alternative.
Q: WHICH VERSION SHOULD I USE? A: FREE REIN
As language changes according to usage and as the term free reign makes perfect sense in its own right, it is difficult to claim that free reign is wrong. However, we would advise that you play it safe and go for free rein. None of readers will baulk at the original version.