On my shelf I keep a first edition of the American Heritage Dictionary of the English Language. On its back cover is a deep dent from when I tried to use the dictionary to pound down a door hinge.

(Oxford University Press)

I keep this old dictionary for two reasons. First as a treasure: A dictionary becomes more beloved as it ages. And second as a reminder: No matter how much you love it, a dictionary cannot solve problems for which it was not designed.

That old book came to mind last month when I saw an online petition to the publisher of the Oxford Junior Dictionary. The signers wanted the editors to restore some words about nature that had been removed — words like acorn, cygnet, heron, ivy and nectar. These lovely, outdoorsy words had been replaced in the Oxford Junior Dictionary with words like blog, chatroom and celebrity, so sorrow is certainly appropriate, though this isn’t the first spasm of resistance. A conservationist objected to the lost nature words almost a decade ago. A cadre of authors including Margaret Atwood wrote a letter to Oxford University Press in 2015, again complaining about the errant nature words. And now comes Change.org, and everybody can get into the act: The petition has nearly 200,000 signatures. For a dictionary of around 10,000 words aimed at 7-year-olds, that’s a lot of attention.

And that’s wonderful: The people at Oxford have responded with a polite note about word selection and space limitation. Everybody feels good reminding each other how important nature is. We use terms like “nature deficit disorder” to describe the negative effects on people — especially the children the Oxford Junior serves — when they lose track of the natural world.

Yet this petition raises another issue, too: What is a dictionary’s job? Is it descriptive or prescriptive? That is, should it describe how people use words or should it tell people how to use words?

Here’s a metaphor that might help. If you get your picture taken and you think your hair looks frightful, is the problem your hair or the picture? If all you want is a better picture, you could manipulate the image, but you’ll have better results addressing your hair. Just so, the dictionary offers a picture of how we’re using language. If you don’t like what it’s showing, ask yourself what’s really going on.

The world is a place where children spend less time than we’d like in natural settings. Including more nature words in the dictionary might mask that problem but won’t solve it.

We’ve been having this discussion for centuries. In his famous dictionary of 1755, Samuel Johnson himself set out to, in his own words, “fix our language, and put a stop to those alterations which time and chance have hitherto been suffered to make in it without opposition.” Good luck with that.

“I have indulged expectation,” Johnson admits he very quickly learned, “which neither reason nor experience can justify.” The language and the world change; the dictionary reflects those changes. That’s how languages work.

The most famous debate on this topic in the United States surrounded the publication of Webster’s Third New International Dictionary in 1961. The Second, which had come out in 1934, had been as much guide as dictionary. Its more than 3,000 pages included stern notes on many of its 600,000 words, eschewing variant pronunciation and usage. It radiated “an almost unanswerable air of authority,” according to the magazine of the National Endowment for the Humanities. But then in 1961, out came the Third, which dropped the notion that it had to guard the public from improper pronunciation or usage. “Ain’t” showed up among its entries, for instance, and newspapers hyperventilated. The Toronto Globe & Mail dolefully lamented “The Death of Meaning.”

But that was misguided. Webster’s Third represented only the death of lexicographic gatekeeping. Even the American Heritage Dictionary, which emerged in response, represents rather than leads.

The Oxford Junior Dictionary has a job to do: It needs to help young children look up words they encounter and, by doing so, learn to use a dictionary. It needs to reflect the curriculum kids learn and the topics they encounter. Not that we don’t deplore a world in which acorn and cygnet are omitted from the top 10,000 words, but I’m not sure the dictionary is the hill to die on in that fight.

And if you want your kids to be familiar with cygnets and acorns, don’t worry about whether they’ll find those words in a book. Take them outside.

Scott Huler’s seventh book of nonfiction, “A Delicious Country,” about 18th-century explorer John Lawson, will be published by the University of North Carolina Press.