At which Oxford institution did J.R.R. Tolkien work on the Oxford English Dictionary?

J.R.R. Tolkien worked on the Oxford English Dictionary. After the First World War, he joined the dictionary’s staff and worked on words beginning with “wag-” through “war-.”

Tolkien’s contribution involved tracing word histories, meanings, spellings, and forms across historical sources. The experience gave him intensive practical knowledge of how English developed over time. He later described the work as influential on his understanding of language and on his professional direction as a philologist.

The OED was not simply a dictionary being written from scratch in one office. It was a large scholarly project built from quotations and historical evidence. Tolkien’s work there preceded his academic appointments at Leeds and Oxford. The Bodleian Library and Oxford University Press are related to Oxford scholarship, but neither is the institution named by this answer.