Haiku (俳句, ) is a type of short form poetry that originated in Japan. Traditional Japanese haiku consist of three phrases composed of 17 morae (called on in Japanese) in a 5, 7, 5 pattern; that include a kireji, or "cutting word"; and a kigo, or seasonal reference. However, haiku by classical Japanese poets, such as Matsuo Bashō, also deviate from the 17-on pattern and sometimes do not contain a kireji. Similar poems that do not adhere to these rules are generally classified as senryū. Haiku originated as an opening part of a larger Japanese genre of poetry called renga.
https://en.wikipedia.org/wiki/Haiku