Rain - reign - rein

Rain, reign and rein form one of the sets of homophones listed by the then Poet Laureate Robert Bridges.
(For more, see Bridges homophones). AWE has a category listing our articles on each of these.

All three words are pronounced to ryme with 'plain' (and 'plane', IPA: /reɪn/. They are three homophones that can be, and have been, confused. Don't confuse them.

• Rain is known to all who live in the UK: it is the water that falls from the clouds, and forms a conspicuous part of our weather. The noun rain is not normally countable, alt6yhough in some climates, regular periods of rain ('rainy seasons') are called The Rains.. The verb 'to rain' is impersonal, as in "It is raining."
• 'To reign' is, in the constitutional and political sense, 'to rule'. It was applied in monarchies like the UK and its constituent parts to the duties of a reigning king or queen. (Etymologically, this word is related to 'regal' and 'regular', which may help you remember its spelling.) Nowadays in the UK, these duties are largely exercised on the monarch's behalf by 'HMG' (Her [or His] Majesty's Government). The noun 'a reign' means a period of rule, and is often the period of the monarch's rule: "The reign of Elizabeth I was from 1558 to 1603." Both noun and verb may be used figuratively, both about people who are not part of national government - "After a short reign, the new manager was sacked by the Board" - and more broadly to give an idea of dominance: "In the Library, silence reigned." In sport, it refers to dominance by a team or individual: "Emil Zatopek reigned supreme in distance running at the 1952 Olympics". (See -eign for more about the spelling and pronunciation of this pattern of letters.)
• Rein is also a noun, and often a countable one. It means the thin strip of leather held by a rider which leads to a horse's mouth, and which is the means for the rider to control the animal. The noun is quite often used in the plural form. To 'hold the reins' is, both literally and figuratively, to be in charge. This is sometimes used figuratively in various phrases denoting greater or less control: 'to give someone free rein', for example, is 'to give him his head', or more freedom; 'to rein someone in' is to exercise more control.

Confusion over the correct spelling can arise from the closeness of the idea of 'control'. In the case of rein, the idea is of controlling an animal. In reign, the fundamental idea is of controlling a political unit. Try to be clear about which image you are seeking to use - or, if you are using a cliché, which image is in the mind of the originator, or previous users. 'Free reign' must normally be an error.

• • Strangely enough, the root of reindeer, the 'Christmas animal' (Rangifer tarandus), is not connected to rein in the sense above - although the animal is commonly harnessed. One of its names in Icelandic and other Germanic languages is the simple monosyllable ren (in Danish and Norwegian, where it is sometimes spelled rein, and Swedish), which was hreinn in Old Icelandic. (Until the twentieth century, the animal was sometimes called the rein in English, now an obsolete use.) OED says it is "of uncertain origin", but suggests that it may be to do with the animal's "antlers or 'horns'". This has been combined with the common 'deer' in Germanic languages, with variations in detailed form (Icelandic hreindyr, Swedish rendjur and German Rentier, for example).
• There is also a near homophone in the verb 'to arraign'. The primary current use in modern English is in Law, where it is a formal word meaning 'to accuse in a court', or 'to bring an indictment'. It is also used figuratively: a politician's behaviour may be arraigned by newspapers.