The foot is the basic metrical unit that generates a line of verse in most Western traditions of poetry, including English accentual-syllabic verse and the quantitative meter of classical ancient Greek and Latin poetry. The unit is composed of syllables, the number of which is limited, with a few variations, by the sound pattern the foot represents. The most common feet in English are the iamb, trochee, dactyl, and anapest. Contrasting with stress-timed languages, in syllable-timed languages such as French, a foot is a single syllable.
The English word "foot" is a translation of the Latin term pes, plural pedes; the equivalent term in Greek, sometimes used in English as well, is metron, plural metra, which means "measure". The foot might be compared to a measure in musical notation.
The foot is a purely metrical unit; there is no inherent relation to a word or phrase as a unit of meaning or syntax, though the interplay among these is an aspect of the individual poet's skill and artistry.
The poetic feet in classical meter 
Below are listed the names given to the poetic feet by classical metrics. The feet are classified first by the number of syllables in the foot (disyllables have two, trisyllables three, and tetrasyllables four) and secondarily by the pattern of vowel lengths (in classical languages) or syllable stresses (in English poetry) which they comprise.
The following lists describe the feet in terms of vowel length (as in classical languages). Translated into syllable stresses (as in English poetry), 'long' becomes 'stressed' ('accented'), and 'short' becomes 'unstressed' ('unaccented'). For example, an iamb, which is short-long in classical meter, becomes unstressed-stressed, as in the English word "betray".
¯ = stressed/long syllable, ˘ = unstressed/short syllable (macron and breve notation)
|˘ ˘||pyrrhus, dibrach|
|¯ ˘||trochee, choree (or choreus)|
|˘ ˘ ˘||tribrach|
|¯ ˘ ˘||dactyl|
|˘ ¯ ˘||amphibrach|
|˘ ˘ ¯||anapest, antidactylus|
|˘ ¯ ¯||bacchius|
|¯ ¯ ˘||antibacchius|
|¯ ˘ ¯||cretic, amphimacer|
|¯ ¯ ¯||molossus|
|˘ ˘ ˘ ˘||tetrabrach, proceleusmatic|
|¯ ˘ ˘ ˘||primus paeon|
|˘ ¯ ˘ ˘||secundus paeon|
|˘ ˘ ¯ ˘||tertius paeon|
|˘ ˘ ˘ ¯||quartus paeon|
|¯ ¯ ˘ ˘||major ionic, triple trochee|
|˘ ˘ ¯ ¯||minor ionic, double iamb|
|¯ ˘ ¯ ˘||ditrochee|
|˘ ¯ ˘ ¯||diiamb|
|¯ ˘ ˘ ¯||choriamb|
|˘ ¯ ¯ ˘||antispast|
|˘ ¯ ¯ ¯||first epitrite|
|¯ ˘ ¯ ¯||second epitrite|
|¯ ¯ ˘ ¯||third epitrite|
|¯ ¯ ¯ ˘||fourth epitrite|
|¯ ¯ ¯ ¯||dispondee|
- The Oxford Dictionary of Literary Terms (2008) Chris Baldick, Oxford University Press.
- The Oxford Companion to Classical Literature (1976) Edited by M. C. Howatson, Oxford University Press Inc.