Monosyllabic: one foot per line
Dimeter: two feet per line
Trimeter: three feet per line
Tetrameter: four feet per line
Pentameter: five feet per line
Hexameter: six feet per line
Heptameter: seven feet per line

Most poetry in English is divided into tetrameter or pentameter lines, though we'll probably see evidence of other meters. Generally, once a poet chooses the meter count, he or she will stick with it throughout, modulating it only occasionally for effect.

What, however, does a "foot" consist of? Well, in Old-English poetry, feet are simply stressed syllables: four of them and you've got a line, with any number of unstressed syllables surrounding them. By the Renaissance, however, there was a much more strict set of rules (based on Greek scansion) of what made a foot. Thus we get these sorts of feet:

Iambic (iamb): unstressed followed by stressed syllable (marked: ~/)
        uncouth delight return appeal

Trochaic (trochee): stressed followed by unstressed syllable (marked: /~)
        easy cursor weeping angry

Anapestic (anapest): two unstressed followed by a stressed (marked: ~~/)
        brigadier rearrange disallow

Dactylic (dactyl): stressed followed by two unstressed (marked: /~~)
        envelope Renaissance implicate

Spondaic (spondee): two stressed syllables (marked: //)
        headache armband

With these we can "scan" the meter of the poem to see how its meter helps us make sense of a line, by giving stress to words or syllables that we might not otherwise give stress to. It also is the music of poetry, giving the structure that the words form themselves to, the framework that poetry is built upon. Whenever you've got to close-read poetry (although it's not mandatory this time around) it's important to scan it to see if the sense that you make of the poem is reinforced or countered by the meter (it gives you something to talk about other than just "what it means," which is only part of what poetry is about.) Scanning ought to allow you to sort of get in the head of the poet to see what she or he was doing when she or he worded something one way instead of another; and eventually that ought to help your interpretations.

Some Sample Poems to Practice On