" Every entry, whether revised or reviewed, goes through multiple editing passes. The definer starts the job, then it’s passed to a copy editor who cleans up the definer’s work, then to a bunch of specialty editors: cross-reference editors, who make sure the definer hasn’t used any word in the entry that isn’t entered in that dictionary; etymologists, to review or write the word history; dating editors, who research and add the dates of first written use; pronunciation editors, who handle all the pronunciations in the book. Then eventually it’s back to a copy editor (usually a different one from the first round, just to be safe), who will make any additional changes to the entry that cross-reference turned up, then to the final reader, who is, as the name suggests, the last person who can make editorial changes to the entry, and then off to the proofreader (who ends up, again, being a different editor from the definer and the two previous copy editors). After the proofreaders are done slogging through two thousand pages of four-point type, the production editors send it off to the printer or the data preparation folks, and then we get another set of dictionary pages (called page proofs) to proofread. This process happens continuously as we work through a dictionary, so a definer may be working on batches in C, cross-reference might be in W, etymology in T, dating and pronunciation in the second half of S, copy editors in P (first pass) and Q and R (second pass), while the final reader is closing out batches in N and O, proofreaders are working on M, and production has given the second set of page proofs to another set of proofreaders for the letter L. We all stagger our way through the alphabet until the last batch, which is inevitably somewhere near G, is closed. By the time a word is put in print either on the page or online, it’s generally been seen by a minimum of ten editors. Now consider that when it came to writing the Collegiate Dictionary, Eleventh Edition, we had a staff of about twenty editors working on it: twenty editors to review about 220,000 existing definitions, write about 10,000 new definitions, and make over 100,000 editorial changes (typos, new dates, revisions) for the new edition. Now remember that the 110,000-odd changes made were each reviewed about a dozen times and by a minimum of ten editors. The time given to us to complete the revision of the Tenth Edition into the Eleventh Edition so production could begin on the new book? Eighteen months. "
― Kory Stamper , Word by Word: The Secret Life of Dictionaries