Rhythm

Is a complex word, the meaning which concerns us refers to "Regularity in the repetition in time or space (New Shorter Oxford English Dictionary, electronic edition, London: TLC, 1997). Thus in poetry (or music) rhythm is the patterned repetition of sound.

The classical precedents of European poetry worked with either long and short, or stressed and unstressed, syllables "da dum dum da da dum". For some time European scholars tried to find such patterns in classical Hebrew poetry. It is now clear that they are absent, but that patterns of lines of similar length are built up. (There is still discussion about how one measures "length". My own feeling is that word-units defined by stress give the most useful results.)