A trochee is a metrical foot used in formal poetry. It consists of a long syllable followed by a short one.

Apart from the famous case of Longfellow's Hiawatha, this metre is rare in English verse, except with an extra long syllable added to each line, as in this example from Tennyson:

Go not, happy day,

From the shining fields;

Go not, happy day,

Till the maiden yields.

Perhaps owing to its simplicity, though, trochaic meter is fairly common in children's rhymes:

Peter, Peter pumpkin-eater

Had a wife and couldn't keep her.

Twinkle, twinkle, little star

How I wonder what you are.

Often a few trochees will be interspersed among iambs in the same lines to develop a more complex or syncopated rhythm. Compare (William Blake):

Tyger, Tyger, burning bright

In the forests of the night

These lines are primarily trochaic, with the last syllable dropped so that the line ends with a stressed syllable to give a strong rhyme or masculine rhyme. By contrast, the intuitive way that the mind groups the syllables in later lines in the same poem makes them feel more like iambic lines with the first syllable dropped:

Did he smile his work to see?

In fact the surrounding lines by this point have become entirely iambic:

And when the stars threw down their spears

And watered Heaven with their tears

. . .

Did he who made the lamb make thee?

See Good King Wenceslas.