Upvote:7
It's a bit of both:
The first attestations of the word mail are in Old French and Anglo-Norman: maille, maile, or male or other variants, which became mailye, maille, maile, male, or meile in Middle English.
The modern usage of terms for mail armour is highly contested in popular and, to a lesser degree, academic culture. Medieval sources referred to armour of this type simply as mail; however, chain-mail has become a commonly used, if incorrect, neologism first attested in Sir Walter Scott's 1822 novel The Fortunes of Nigel.
As a further bit of context, the French word for it is "cotte de mailles", with "cotte" being the word that gave coat, and "mailles" being the word that gave mail. So mail coat, if you will.