A univocalic is a poem that uses only one vowel. This example was composed by Charles Bombaugh in 1875:
No monk too good to rob, or cog or plot.
No fool so gross to bolt Scotch collops hot.
From Donjon tops no Oronooko rolls.
Logwood, not lotos, floods Oporto’s bowls.
Troops of old tosspots oft to sot consort.
Box tops odd schoolboys oft do flog for sport.
No cool monsoons blow soft on Oxford dons,
Orthodox, jog-trot, book-worm Solomons!
Bold Ostrogoths of ghosts no horror show.
On London shop-fronts no hop-blossoms grow.
To crocks of gold no dodo looks for food.
On soft cloth footstools no old fox doth brood.
Long storm-tost sloops forlorn work on to port.
Rooks do not roost on spoons, nor woodcocks snort,
Nor dog on snowdrop or on coltsfoot rolls,
Nor common frog concocts long protocols.