MIDDLE-EARTH TIMELINE
Eldamo, An Elvish Lexicon, is Paul Strack's reference on Tolkien's invented languages, above all Quenya and Sindarin. Online since January 2015 and still updated several times a year, it collects every published word with its source, analyses roots and derivations, and follows how Tolkien's ideas about his languages changed over time.
It offers word searches for beginners and for researchers, essays on the Elvish languages, and the whole dataset is free under a Creative Commons licence. If you want to know what a name means, or write a sentence in Quenya, this is the place to start.
Paul Strack's lexicon of Tolkien's Elvish languages, with every published word, its source and its history.