What's the Most Complicated Word in English? According to the editors of the Oxford English Dictionary, the most complicated word in the English language is something we're all familiar with. Believe it or not, the three-lettered word “run” yields as many as 645 different meanings and this is only for the verb. The most recent edition of the dictionary used as many as 75 columns for this word alone. Behind these columns of description is nine months of research and compilation from one professional lexicographer, Peter Gilliver. Before publication, the letter R required more than nine months to harness a vast array of connotations that the word had been associated with.