Haiku is a traditional form of Japanese poetry, consisting of one unified thought, usually about nature. Historically each haiku had 17 syllables in three lines: 5-7-5. More recently it has been adapted to have fewer than 17 syllables and no specific line length. Senryu is similar to haiku, but is about human nature. For more information check out Wikipedia.
More about haiku etcetera
Haiga is haiku together with art or photography
Tanka is haiku together with a paragraph of prose
Halibun is haiku with longer prose
Senryu are haiku about human foibles or situations, often cynical or darkly humorous.
