Ancient Mesopotamians planted walnut groves and harvested the wood and the nuts. In Greek mythology, the goddess Dionysus was transformed into a walnut tree after she died. And the name of the walnut comes from the ancient Romans.
Here's a better account of the story (which in the above case seems to be a case of a reporter taking notes rather carelessly) ... from the Ancient Library's online version of Smith's Dictionary of Greek and Roman Biography and Mythology s.v. Dion [sc. Apollo has already visited Dion and gave his daughters the gift of prophecy, with conditions, of course]:
Afterwards Dionysus also came to the house of Dion; he was not only well received, like Apollo, but won the love of Carya, and therefore soon paid Dion a second visit, under the pretext of consecrating a temple, which the king had erected to him. Orphe and Lyco, however, guarded their sister, and when Dionysus had reminded them, in vain, of the command of Apollo, they were seized with raging madness, and having gone to the heights of Taygetus, they were metamorphosed into rocks. Garya, the beloved of Dionysus, was changed into a nut tree, and the Lacedaemonians, on being informed of it by Artemis, dedicated a temple to Artemis Caryatis.
On the etymological side of things, Botanical.com's page is rather more accurate ...
With all the foregoing in mind, how would one render WTF in a Latin acronym?