Isoictic metre: a metre (also called demotic or accentual) in which each line has a fixed number of beats (usually four or eight) but no fixed number of syllables; where there are only three sounded beats there will be a fourth occurring in silence (a rest), indicated in what follows by “<!>” (if you try clapping on the beats you will find yourself wanting to clap on the rests as well). The following nursery-rhyme has been slightly altered to show that equivalent four-beat lines may contain anything from 3 to 13 syllables :
Péase pórridge hót <!> 4 syllables
Péase pórridge cóld <!> 4 …