What's the noun for haikus? Here's the word you're looking for.
haiku
A Japanesepoem of a specific form, consisting of three lines, the first and last consisting of five morae, and the second consisting of seven morae, usually with an emphasis on the season or a naturalistic theme.
A three-line poem in any language, with five syllables in the first and last lines and seven syllables in the second, usually with an emphasis on the season or a naturalistic theme.