"Huckleberry Finn" is a character in a book by American author Mark Twain. His name comes from the idea of a huckleberry, which is a small fruit, not much good for anything, and used to mean something worthless. In the book, Huckleberry Finn comes from a poor background and isn't thought much of, but proves to be a loyal and trustworthy friend.
The idea was used in the song, Moon River, which is thought to be about the Mississippi river (wider than a mile). Ini the song, the river is referred to as the singer's "Huckleberry friend" - in other words, something that people generally take little notice of, but which is actually there, day in, day out, and never goes away.
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