An iamb, trochee and spondee are two-syllabic feet in a verse. A dactyl is a three-syllabic foot in a verse. In a dactylic meter a stressed syllable is followed by two unstressed syllable.
Alfred, Lord Tennyson's poem The Charge of the Light Brigade is a good example of a poem written in dactylic meter, but it uses trochees as well.
Half a league, half a league,
Half a league onward,
All in the valley of Death
Rode the six hundred.
"Foreward, the Light Brigade!
Charge for the guns!" he said.
Into the valley of Death
Rode the six hundredThe mono-syllabic word Death is atypical of the metrical pattern and it is in order to draw attention to death.
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