Hiku is any English language variation on the Japanese haiku

As with the Japnese haiku itself rhyme is permissable  where it is 'inevitable as part of the natural meaning and its effect is a delightful surprise' as Basho (the master haikuist)illustrates here (one of many of his rhymed traditional Japanese haiku))

The autumn moon is bright

Sea-waves whirl up to my gate

Crested silvery white