Douglas Harper compiled the etymology dictionary to record the history and evolution of more than 30,000 words, including slang and technical terms. The core body of its etymology information stems from Ernest Weekley's An Etymological Dictionary of Modern English (1921). Other sources include the Middle English Dictionary and the Barnhart Dictionary of Etymology (by Robert Barnhart and others), although the sources for each entry are not stated. In producing his large dictionary, Harper says that he is essentially and for the most part a compiler, an evaluator of etymology reports which others have made. Harper works as a Copy editor/Page designer for LNP Media Group.
The Online Etymology Dictionary has been referenced by Oxford University's "Arts and Humanities Community Resource" catalog as "an excellent tool for those seeking the origins of words" and cited in the Chicago Tribune as one of the "best resources for finding just the right word". It is cited in academic work as a useful, though not definitive, reference for etymology. In addition, it has also been used as a data source for quantitative scholarly research.