What does the name Thranduil mean?
Tolkien never explains what the name Thranduil translates into. BUT: People who study the Elvish language have LOTS of differing theories. Below are three separate translations of the name Thranduil from three different sources: (links given for each) From The Encyclopedia of Arda : “Tolkien’s reticence on the meaning of Thranduil’s name needn’t prevent us from indulging in a little guesswork. One reasonable possibility for the name’s source would be tharanduil, a combination of elements that means ‘beyond the long river’. Though this is no more than speculation, Thranduil’s history of travelling eastward from Lindon and ruling a kingdom across the Great River Anduin lends it some credibility.” From The Thain’s Book: “The meaning of Thranduil is not given. One possible interpretation is “across the Great River.” The element thar means “across, beyond.” The element anda means “long” and duin or duil means “river.” These elements are also combined in the name of the Great River Anduin.”