What is the in-universe reason for the name "Fairy Tail"? In Fairy Tail, the guild is named "Fairy Tail". While there does seem to be a range of ethnicities within the names (Natsu vs. Lucy), it just seems like an odd misspelling of "fairy tale", which is a very specific thing that seems to be totally unrelated to the guild itself.

What is the in-universe reason given for that being the name of the guild, if there is a reason given?
From Makarov's history based on Wikia:


  The guild was named 'Fairy Tail' as the eternal mystery behind whether fairies had tails or not, or if they even existed, was like an eternal adventure.


So I guess the guild's (Fairy Tail's) purpose is to have a great adventure as if they are solving the mysteries about fairies.