A univocalic is a type of lipogrammatic constrained writing that uses only a single vowel, "A", "E", "I", "O", or "U", and no others.
- One of the best-known univocalic poems was written by C.C. Bombaugh in 1890 using "O". Bombaugh's work is still in print. An example couplet:
- No cool monsoons blow soft on Oxford dons,
- Orthodox, jog-trot, book-worm Solomons
- The Austrian poet Ernst Jandl composed his univocalic poem "Ottos Mops" (Otto's Pug) from German words with only the vowel "O".
- A contemporary example of English-language univocalic poems is Canadian poet Christian Bök's text Eunoia, published by Coach House Press in 2001.
- An example of a univocalic novella is Georges Perec's Les Revenentes (sic), in which the vowel "E" is used exclusively.