What is Haiku?

From Microsoft Encarta...

Haiku, Japanese verse form, notable for its compression and suggestiveness. It consists of three unrhymed lines of five, seven, and five syllables.

Traditionally and ideally, a haiku presents a pair of contrasting images, one suggestive of time and place, the other a vivid but fleeting observation. Working together, they evoke mood and emotion. The poet does not comment on the connection but leaves the synthesis of the two images for the reader to perceive. A haiku by the poet Basho, considered to have written the most perfect examples of the form, illustrates this duality:

Now the swinging bridge
Is quieted with creepers ...
Like our tendrilled life.