“When is a ream of paper not a ream of paper?” reader J. asked us in the subject line of his e-mail to the Consumerist tipline. We were hoping that this was the setup to a totally great joke, but it wasn’t. Instead, he sent us a dismaying photo that shows Target is trying to undo centuries of history and redefine what a “ream” of paper is.

We are not being hyperbolic here. Well, okay, maybe a little. But time for a history lesson: The term “ream” predates your neighborhood big-box office supply store, predates the Dunder-Mifflin Paper Company, and even predates that typing pool your grandma was in in the ’50s.

“Ream” has meant five hundred sheets of paper since the 16th century. Well, around five hundred. According to the repository of all human knowledge, Wikipedia, which cites actual books on the history of publishing, a “ream” of paper has ranged from around 425 to around 550 sheets over the centuries, but usually comes in between 480 and 500.

Does this package from Target say “one ream” on it? No. It does not. But like the four-pound bag of sugar, it looks and feels about the same as the quantity you’re used to buying, and customers will pick it up out of habit without even noticing. Maybe.

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