(plural haiku) is a very short form of Japanese poetry. It is typically characterised by three qualities:

• The essence of haiku is "cutting" (kiru). This is often represented by the juxtaposition of two images or ideas and a kireji ("cutting word") between them, a kind of verbal punctuation mark which signals the moment of separation and colors the manner in which the juxtaposed elements are related.
• Traditional haiku consist of 17 on (also known as morae), 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.