J.R.R. Tolkien began working on the Oxford English Dictionary in 1919.
After serving in the British Army during the First World War and recovering from illness, Tolkien joined the staff preparing the Oxford English Dictionary. He worked mainly on the history and etymology of words beginning with the letter W, including technical and Germanic vocabulary.
The dictionary project helped strengthen Tolkien’s professional reputation as a philologist. His work involved tracing word forms through historical sources and comparing related languages, methods that also informed his construction of fictional languages. Tolkien later described his dictionary experience as valuable training in how words change over time.
Tolkien’s OED work lasted until 1920, when he left to become a reader in English language at the University of Leeds. The dictionary was not a single-volume project completed during his employment; it was an enormous collaborative undertaking that continued for decades.