This blog post is in English only, because it specifically refers to the English terms for our hobby. Luckily in Dutch, 'maliën' only has one meaning.
So, what is what we make in this hobby called? Chainmail? Chain mail? Maille? Chainmaille? Long story short, all of these are right.
Language is a funny thing. As long as enough people agree that one way of writing is the right way, that way of writing is correct, and even those who compose dictionaries will follow suit. This may change over time - one way to write a word may be considered archaic, since few people now write it that way.
The French and the Victorians
Some people will tell you 'chainmail' is a pleonasm, since 'mail' already means 'a fabric made of rings', from the French word 'maille'.
In French, 'Maille' means 'mesh', and can also refer to nets. 'Cotte de mailles' is a clearer translation, but that specifically translates to a chainmail shirt or hauberk. French is a language which tries to do a lot with as few words in its vocabulary as possible.
The Victorian English expanded the types of 'mail' to include 'plate mail', 'scale mail', and other forms of armour, even though plate armour, for instance, has nothing to do with mesh. They did have a tendency both to co-opt other languages' vocabulary, and to over-categorise all things in the world.
Chainmail, or chain mail?
Since 'mail' can also have other meanings (letters, for instance), it is very useful to have the term 'chainmail'. 'Chain mail' later became associated with a type of spam where the recipient of a letter (or later, email) had to send one or more letters to their friends so as not to 'break the chain', lest misfortune befell them.
While technically both forms of spelling can refer to both types of mail, the community generally decided that Chainmail was distinct enough.
Maille, or chainmaille?
Some parts of the community preferred to have a word which was completely separate from both the pleonasmic 'chainmail' and spammy 'chain mail', and they chose to use the original French spelling, 'maille'. Others felt that was not clear enough, and chose an amalgam of the French and Victorian English words, 'chainmaille'.
As long as your meaning comes across, any of them are fine to use. None of them are perfect, but none of them are completely without merit either.