Poetic rhythm - some useful terms

Reprinted with the kind permission of Professor Jack Lynch:

Glossary of Literary and Rhetorical Terms By Jack Lynch, Rutgers University
Last revised 3 August 1999
http://andromeda.rutgers.edu/~jlynch/Terms/index.html
Foot
A foot is the basis of meter: that is, the regular unit of rhythm which, when repeated, makes up a verse. Although the basis of meter in the classical languages was "quantitative" — i.e., "long" and "short" syllables were based on the actual amount of time it took to speak the syllables — and some English poets made experiments in this direction, virtually all English feet are based on a pattern of stressed and unstressed syllables. Still, the terms are usually imported from Greek and Latin versification, and you may hear "long" and "short" where "stressed" and "unstressed" are meant.
Each common foot comprises two or three syllables: either one or two stressed syllables, and zero, one, or two unstressed syllables. The common feet in English:
Duple Meters:
Unstressed, stressed: iamb
Stressed, unstressed: trochee
Stressed, stressed: spondee
Triple Meters:
Stressed, unstressed, unstressed: dactyl
Unstressed, unstressed, stressed: anapest
Unstressed, stressed, unstressed: amphibrach
Meter is usually described by giving both the kind of feet (above) and the number in each verse. The basic meters are:
One foot: monometer (accent on the first and third syllables: MAH-no-MEE-ter)
Two feet: dimeter (accent on the first syllable, which sounds like "dim")
Three feet: trimeter (accent on the first syllable, which sounds like "trim")
Four feet: tetrameter (accent on second syllable)
Five feet: pentameter (accent on the second syllable)
Six feet: hexameter (accent on the second syllable)
Although in most kinds of English verse one type of foot predominates in each line, substitutions are possible.
Anapest
A kind of metrical foot. An anapest (or anapaest) comprises two unstressed syllables and one stressed one: for example, "unabridged," "intercede," "on the loose."
Dactyl
A kind of metrical foot. A dactyl is a stressed syllable followed by two unstressed syllables: for example, "Canada," "holiday," "camouflage." (The name comes from the Greek for "finger" — as in pterodactyl, "winged-finger" — and you can remember the pattern by thinking of the three joints in a finger: long, short, short.)
Amphibrach
A metrical foot. The term means "short (brachys) on either side (amphi)," which perfectly describes the foot — a stressed syllable surrounded by two unstressed syllables. Some amphibrachs: "another," "uncommon," "instead of."
Trochee, Trochaic
A kind of metrical foot. A trochee (the adjective is "trochaic") is a stressed syllable followed by an unstressed one:
Róund abóut the cáuldron gó,
Ín the póisoned éntrails thrów.
A kind of metrical foot. An iamb (the adjective is "iambic") is an unstressed syllable followed by a stressed one.
They álso sérve who ónly stánd and wáit.