pan.ˈtüm noun
( -s )
Etymology: French, from Malay pantun
: a series of quatrains rhyming abab in which the second rhyme of a quatrain recurs as the first in the succeeding quatrain, each quatrain introduces a new second rhyme (as bcbc, cdcd ), and the initial rhyme of the series recurs as the second rhyme of the closing quatrain ( xaxa )