An anapaest is a metrical foot used in formal poetry

Poetry

Poetry is a form of literary art in which language is used for its aesthetic and evocative qualities in addition to, or in lieu of, its apparent meaning...

. In classical quantitative meters it consists of two short syllables followed by a long one; in accentual stress meters it consists of two unstressed syllables followed by one stressed syllable. It may be seen as a reversed dactyl

Dactyl (poetry)

A dactyl is a foot in meter in poetry. In quantitative verse, such as Greek or Latin, a dactyl is a long syllable followed by two short syllables, as determined by syllable weight...

. This word comes from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 ανάπαιστος, anápaistos, literally "struck back" (a dactyl reversed), from 'ana-' + '-paistos', verbal of παίειν, paíein: to strike.

Because of its length and the fact that it ends with a stressed syllable and so allows for strong rhymes, anapaest can produce a very rolling, galloping feeling verse, and allows for long lines with a great deal of internal complexity.

Examples

Trimeter
Here is an example from William Cowper

William Cowper

William Cowper was an English poet and hymnodist. One of the most popular poets of his time, Cowper changed the direction of 18th century nature poetry by writing of everyday life and scenes of the English countryside. In many ways, he was one of the forerunners of Romantic poetry...

's "Verses Supposed to be Written by Alexander Selkirk" (1782), composed in anapaestic trimeter

Trimeter

In poetry, a trimeter is a metre of three metrical feet per line—example:...

:

I must finish my journey alone

Tetrameter
An example of anapaestic tetrameter is the anonymously published A Visit From St. Nicholas:

Twas the night before Christmas and all through the house

The following is from Byron

George Gordon Byron, 6th Baron Byron

George Gordon Byron, 6th Baron Byron, later George Gordon Noel, 6th Baron Byron, FRS , commonly known simply as Lord Byron, was a British poet and a leading figure in the Romantic movement...

's The Destruction of Sennacherib

The Destruction of Sennacherib

The Destruction of Sennacherib is a poem by Lord Byron first published in 1815 in his Hebrew Melodies. It is based on an event described in the Bible during the campaign by Assyrian king Sennacherib to capture Jerusalem...

:

The Assyrian came down like a wolf on the fold

And his cohorts were gleaming in purple and gold

And the sheen of their spears was like stars on the sea

When the blue wave rolls nightly on deep Galilee.

Hexameter
An even more complex example comes from Yeats

William Butler Yeats

William Butler Yeats was an Irish poet and playwright, and one of the foremost figures of 20th century literature. A pillar of both the Irish and British literary establishments, in his later years he served as an Irish Senator for two terms...

's The Wanderings of Oisin

The Wanderings of Oisin

The Wanderings of Oisin is an epic poem published by William Butler Yeats in 1889 in the book The Wanderings of Oisin and Other Poems. It was his first publication outside of magazines, and immediately won him a reputation as a significant poet....

. He intersperses anapests and iambs, using six-foot lines (rather than four feet as above). Since the anapaest is already a long foot, this makes for very long lines.

Fled foam underneath us and 'round us, a wandering and milky smoke

As high as the saddle-girth, covering away from our glances the tide

And those that fled and that followed from the foam-pale distance broke.

The immortal desire of immortals we saw in their faces and sighed.

The mixture of anapaests and iambs in this manner is most characteristic of late-19th-century verse, particularly that of Algernon Charles Swinburne

Algernon Charles Swinburne

Algernon Charles Swinburne was an English poet, playwright, novelist, and critic. He invented the roundel form, wrote several novels, and contributed to the famous Eleventh Edition of the Encyclopaedia Britannica...

 in poems such as The Triumph of Time

The Triumph of Time

The Triumph of Time is a poem by Algernon Charles Swinburne, published in 1866. It is in adapted ottava rima and is full of elaborate use of literary devices, particularly alliteration. The theme, which purports to be autobiographical, is that of rejected love...

and the choruses from Atalanta in Calydon. Swinburne also wrote several poems in more or less straight anapaests, with line-lengths varying from three feet ("Dolores") to eight feet ("March: An Ode"). However, the anapaest's most common role in English verse is as a comic metre, the foot of the limerick

Limerick (poetry)

A limerick is a kind of a witty, humorous, or nonsense poem, especially one in five-line or meter with a strict rhyme scheme , which is sometimes obscene with humorous intent. The form can be found in England as of the early years of the 18th century...

, of Lewis Carroll

Lewis Carroll

Charles Lutwidge Dodgson , better known by the pseudonym Lewis Carroll , was an English author, mathematician, logician, Anglican deacon and photographer. His most famous writings are Alice's Adventures in Wonderland and its sequel Through the Looking-Glass, as well as the poems "The Hunting of the...

's poem The Hunting of the Snark

The Hunting of the Snark

The Hunting of the Snark is usually thought of as a nonsense poem written by Lewis Carroll in 1874, when he was 42 years old...

, Edward Lear

Edward Lear

Edward Lear was an English artist, illustrator, author, and poet, renowned today primarily for his literary nonsense, in poetry and prose, and especially his limericks, a form that he popularised.-Biography:...

's nonsense poems, T. S. Eliot

T. S. Eliot

Thomas Stearns "T. S." Eliot OM was a playwright, literary critic, and arguably the most important English-language poet of the 20th century. Although he was born an American he moved to the United Kingdom in 1914 and was naturalised as a British subject in 1927 at age 39.The poem that made his...

's Book of Practical Cats, a number of Dr. Seuss

Dr. Seuss

Theodor Seuss Geisel was an American writer, poet, and cartoonist most widely known for his children's books written under the pen names Dr. Seuss, Theo LeSieg and, in one case, Rosetta Stone....

 stories, and innumerable other examples.

Apart from their independent role, anapaests are sometimes used as substitutions in iambic verse. In strict iambic pentameter

Iambic pentameter

Iambic pentameter is a commonly used metrical line in traditional verse and verse drama. The term describes the particular rhythm that the words establish in that line. That rhythm is measured in small groups of syllables; these small groups of syllables are called "feet"...

, anapaests are rare, but they are found with some frequency in freer versions of the iambic line, such as the verse of Shakespeare's last plays, or the lyric poetry of the 19th century.