Pippin on OED

[Bêthberry]

Originally Posted by MatthewM

What's OED?

The Oxford English Dictionary, which Oxford calls the definitive dictionary of the English language.

It is unlike other dictionaries in that they list only current meanings of words while the OED attempts to record every meaning of a word ever had over the last thousand years. And that's a half million words, through their changes in meaning and spelling and pronounciation, as evidenced from texts. It provides examples of the historical meanings with quotations from sources as early as the Old English manuscripts Tolkien studied to the most contemporary sources from around the world.

Look here on the official site for more information about it. It's fairly unique as a dictionary, although, like all human endeavours, it has its blind spots and weaknesses.

The story of its creation can be read in this book: Caught in the Web of Words: James Murray and the Oxford English Dictionary

As davem points out, Tolkien worked on it early in his career.