From NYU he went to the University of Tennessee. There he began working in earnest on his slang dictionary. His doctoral thesis, published in 1980, was A Historical Dictionary of American Slang: Volume I, the Letter A . With some 1,800 definitions and 500 illustrative examples, it served as the model for the magnum opus now in progress.

Lighter’s dictionary constitutes an immense trove of Americana. For example, consider his etymological note on goon , meaning a stupid person:

“Apparently introduced as a nonce term by Frederick Lewis Alien [the social historian].... Alien’s sense, ‘a stolid, usually unimaginative person, especially a writer or public figure,’ seems to have been evanescent: no independent examples are known. All later senses of the word appear to have been inspired by ‘Alice the Goon,’ a fantastic, dull-witted, muscular character who appeared in E. C. Segar’s popular comic strip ‘Thimble Theater, featuring Popeye,’ beginning in 1933.”

This sense of the term then is illustrated with 17 citations, beginning with one from Alien in Harper’s Magazine in 1921 and including a 1948 note by H. L. Mencken that the historian had told him that goon had been used in the Alien family for some time prior to 1921, though Alien himself wasn’t sure where it had come from.

Many of Lighter’s notes spike common myths. An example is his note on crap , which he dates from 1846 in the form of crappy : “The verb probably derives from the noun, and, as the evidence demonstrates, no historical connection exists between this word and the name of the sanitary engineer Thomas Crapper (1837–1910).”

He also has gone to great effort to trace quotations to primary sources. A short note on cowpoke reveals the extent of his research: “Wentworth American Dialect Dictionary (1944), and hence all other standard sources, erroneously cites [ sic ] Croffutt Grip-Sack Guide to Colorado (1881); the word cowpoke is not to be found in that work.” Curiously, for what would seem to be an old Western word, the earliest example of the term comes from the 1920s.

Lighter’s dictionary raises the study of slang to an entirely new level, and it will influence the making of other dictionaries for years to come. For the next generation at least, the basic answer for anyone who has any question about American slang will be “Look it up in Lighter.”

I spoke with Lighter in his office—a small room, jam-packed with books and boxes of filing cards—in the library of the University of Tennessee at Knoxville.

To begin at the beginning, how do you define slang?

One of the things—maybe the main thing—distinguishing slang from other kinds of vocabulary is that it tends to be intentionally undignified, startling, or amusing. It’s notably out of place in the realm of formal English.

Does this mean that unless you have some agreement on what constitutes Standard English, you can’t have slang?

Yes. Slang is a reaction to standard language. To have slang, I think you need to have a tradition of education to emphasize the importance of the standard language. You also need to have a stratified society with a certain amount of mobility in it, so very different kinds of people have opportunities to mingle. Finally, I think you have to have an established cultural tendency toward irreverence. You have to have the standard and at the same time a popular skepticism about it.

So existence of slang presumes a certain amount of development in society, right? When did the concept of slang arise in English-speaking countries?

The word slang started to come into general use in the 1750s, but it wasn’t included in a standard dictionary until 1828, when Noah Webster published his American Dictionary . Webster defined slang simply as “low, vulgar unmeaning language,” which, I think, is very significant. This tells us that he thought of slang as a blanket term for any sort of non-Standard English that the educated public, which was buying his dictionary, would regard as inelegant.

What made people start to become conscious of changes in language, of what was “low” and what wasn’t “low”?

People generally seem to have begun noticing these changes in the eighteenth century. Scholars in the latter half of the seventeenth century started commenting on English usage more critically, and during the mid-eighteenth century questions of propriety of diction become a matter of academic and learned discussion.

In its original sense the word slang appears to have referred to a special language or vocabulary employed by criminals. In the late eighteenth and early nineteenth centuries, however, you see it used increasingly with various nuances, sometimes meaning vulgar language in the broadest sense, sometimes in the sense of nonsense, and sometimes referring specifically to verbal abuse. Even today it continues to be used very loosely. For most people, I think, slang simply means any word or phrase that some English teacher might object to, for whatever reason.