What is the difference between rhythm and metre? Quite simply, metre is a particular kind of rhythm: it is rhythm organised into a regular pattern that can be measured or counted.
Any arrangement of syllables and words will possess a rhythm which is then actualised by the person reading them. This is so even when that reading takes place silently in the reader’s head. The particular rhythm – or sets of rhythms – a reader experiences in a given cluster of words or a larger expanse of text, moreover, will affect the way she or he responds to and interprets those words. Long, flowing sentences produce very different soundscapes from short, staccato ones, for instance, and we duly enter very different emotional and intellectual states of apprehension as we encounter them. Different people may well perceive and activate different rhythms in the same collection of words too and this is likely to be an important factor in shaping the different overall interpretations they then produce.
Rhythm, then, is a quality of language in general and its artful manipulation in works of literature to produce significant effects is exemplified in prose as well as poetry. Nonetheless, for much of its history, poetry has also employed a very specialised form of rhythm that is distinctive to it alone and that is accordingly not available to works of prose. This is metre and it involves the organisation of words into lines that display fairly fixed (and often conventional) regularised patterns of beats and stresses.
In English poetry, metre consists of two principal elements. The first of these is what is conventionally called the “metrical foot.” A foot is in some ways the equivalent of a bar in music and it is characterised by the pattern of stressed and unstressed beats it contains. The most common patterns found in English poetry are (you should place the stress on the DUM in each case):
de DUM (conventionally known as an iamb and thus as an iambic pattern)
DUM de (trochee/trochaic pattern)
DUM de de (dactyl/dactylic pattern)
de de DUM (anapaest/anapaestic pattern)
The second element that determines the kind of metre to which a line (or even a whole poem) adheres is the number of times this pattern, or foot, is repeated in that line (or the majority of the poem’s lines). The most common of these patterns are the iambic pentameter, which contains five iambs like so
de DUM de DUM de DUM de DUM de DUM
and the iambic tetrameter, which contains four iambs like so:
de DUM de DUM de DUM de DUM
In short, a given metre acquires its name from the kind of pattern that dominates in each line (iambic, trochaic, and so on), plus the number of times this pattern repeats itself in each line (pentameter, tetrameter, trimester, dimeter).
As this overview illustrates, much of the terminology that is still used to describe the different metres of English poetry has been borrowed from the Ancient Greeks. This is a shame, partly because it makes these terms difficult to remember; but it is also problematic because English metres are very different in nature and have been established on different principles from those of the Greeks. Thankfully, it is nowadays becoming increasingly acceptable to use simpler terms, such as ‘five beat [or five stress] line’ for the iambic pentameter. For this module, we will keep our language as simple as possible, and use accessible terms such as ‘stress’ and ‘beat’ whenever the requirements of clarity and precision allow.