The Haiku is a short poem of Japanese origin consisting of three lines of rigid structure.
1. A haiku has three
2. Lines, two of which, you’ll notice,
3. Have five syllables.
Lines 1 and 3 have exactly five syllables, no more and no less.
Line 2 consists of seven syllables.
The Haiku is one of the most famous poem structures in the world. Originally, each poem was supposed to represent some startling revelation the author would have about some aspect of Nature. Many modern authors, myself included, disregard this rule and write what we please.