monorhyme
/ˈmɒnə(ʊ)rʌɪm/(also monorime)
noun
1A poem or passage in which all the lines have the same rhyme; rhyming of this kind.
2In plural Lines forming such a poem or passage; the words representing such rhymes.
adjective
Having a single rhyme.
Origin
Mid 18th century; earliest use found in Nathan Bailey (d. 1742), lexicographer and schoolmaster. From mono- + rhyme, after French monorime.