Haiku: is a very short form of Japanese poetry typically characterised by three qualities:
The essence of haiku is the juxtaposition of two images or ideas and a kireji("cutting word") between them.
Traditional haiku consist of 17 sylables in three phrases of 5, 7 and 5 on respectively.
A kigo (seasonal reference), usually drawn from a saijiki, an extensive but defined list of such words. The majority of kigo, but notall, are drawn from the natural world. This, combined with the origins of haiku in pre-industrial Japan, has led to the inaccurate impression that haiku are necessarily nature poems