Metre

Metre is the ideal rhythmic scheme of verse, the generalised law of alternation between strong and weak positions (ictuses and inter-ictic intervals) by which the line is built. In syllabo-tonic versification metre is realised through feet — recurring combinations of stressed and unstressed syllables (iamb, trochee, dactyl, amphibrach, anapaest). Metre must be distinguished from measure: metre is the type (for example, iamb), while measure is the concrete number of feet (iambic tetrameter). An actual poem almost never coincides fully with its metre: it is the deviations from the scheme (pyrrhics, stress shifts) that create the individual rhythmic pattern, while metre remains the background of expectation against which those deviations are perceived.