Two thousand years ago, or thereabouts, the Roman poet Horace wrote a verse epistle giving advice to writers, the Ars Poetica.  The poem insists that different genres require different styles, highflying when actors wear the tragic buskin, informal when they don the comedic sock (see socle).  But Horace adds that in certain circumstances—when characters grieve, for instance—even tragedy needs simplification, needs to rid itself of bombast and sesquipedalia verba, “words [figuratively] a foot and a half long.” Sesquipedalia simply combines the Latin words for “one and a half” and “foot,” and even today the measurement, foot-and-a-half sense survives in the scientific name of the yardlong or Chinese long bean, Vigna unguicolata, subsp. sesquipedalis:

Could this legume have been named by a classically trained, Horace-reading, tape-measure-wielding botanist?  In fact, the bean’s length seems closer to 18 than to 36 inches, sesquipedalis a more accurate descriptor than “yardlong.”

In the seventeenth century sesquipedalia gave rise to the English word “sesquipedalian,” which might refer to a literal length, but much more frequently to verbal length—that is, to elaborate, polysyllabic, often Latinate words, diction meant to dazzle rather than be understood. The OED cites a 1661 reference to “Noddle puzling sesquepedalian words.”   A century earlier, these were called “inkhorn” terms. Holofernes the Pedant or Nutty Professor of Shakespeare’s Love’s Labor’s Lost likes the sound of them on his tongue (“extemporal,” “apostrophus,” “thrasonical,” “peregrinate”), though in the play it’s the clown Costard who achieves the ne plus ultra in sesquipedalianism with the almost completely meaningless, thirteen-syllable-long Latin word honorificabilitudinitatibus.

What interests me about “sesquipedalian” is that the word is itself sesquipedalian: polysyllabic, elaborate, Latin-derived, mouth-filling.  It does not merely signify a meaning, it enacts or embodies that meaning.  It is what it’s about, and so belongs to the category linguists call “autological words” or “autonyms” (“self words”).  For many other examples, including “pentasyllabic,” a term meaning “five-syllabled” that is five syllables long, and “wee,” a very small word meaning “small,” and “green” and “italics,” see the list in Wiktionary.  There can be autological phrases, too.  My favorite is something heard all the time these days, a phrase which might be thought the diametric opposite of “sesquipedalian” because it works by shortening rather than expanding, by excising rather than multiplying syllables.  What do many people say in place of that hoary formula “to make a long story short”?  They say “long story short . . .”