Glossary: Poetic Foot

• Foot: The basic unit of measurement of accentual-syllabic meter. A foot usually contains one stressed syllable and at least one unstressed syllable. The standard types of feet in English poetry are the iamb, trochee, dactyl, anapest, spondee, and pyrrhic (two unstressed syllables).

• Iamb: A metrical foot consisting of an unaccented syllable followed by an accented syllable. The words “unite” and “provide” are both iambic. It is the most common meter of poetry in English (including all the plays and poems of William Shakespeare), as it is closest to the rhythms of English speech. In Robert Frost’s “After Apple Picking” the iamb is the vehicle for the “natural,” colloquial speech pattern: 

"My long two-pointed ladder’s sticking through a tree 

Toward heaven still, 

And there’s a barrel that I didn’t fill 

Beside it, and there may be two or three 

Apples I didn’t pick upon some bough. 

But I am done with apple-picking now. 

Essence of winter sleep is on the night, 

The scent of apples: I am drowsing off."

• Trochee: A metrical foot consisting of an accented syllable followed by an unaccented syllable. Examples of trochaic words include “garden” and “highway.” William Blake opens “The Tyger” with a predominantly trochaic line: “Tyger! Tyger! Burning bright.” Edgar Allan Poe’s “The Raven” is mainly trochaic.

• Dactyl: A metrical foot consisting of an accented syllable followed by two unaccented syllables; the words “poetry” and “basketball” are both dactylic. Tennyson’s “The Charge of the Light Brigade” is written in dactylic meter.

Source: http://www.poetryfoundation.org/learning/glossary-term/foot

For another useful glossary on poetic foot, click here.