A haiku was a type of poetry originating from Japan on the planet Earth.
In 2369, Data composed a haiku and presented it during a poetry recital in Ten Forward. According to Geordi La Forge, the haiku was "clever" but was not able to evoke an emotional response. (TNG: "Schisms")
In a deleted scene, La Forge mentioned that he especially liked the haiku because of its brevity, in contrast to Data's other works.