haikuPronunciation: /ˈhʌɪkuː/Definition of haiku noun (plural same or haikus) a Japanese poem of seventeen syllables, in three lines of five, seven, and five, traditionally evoking images of the natural world. a poem in English written in the form of a haiku. Origin:Japanese, contracted form of haikai no ku 'light verse'haiku in other Oxford dictionaries Definition of haiku in the US English dictionary