A haiku is an ancient form of Japanese poetry, which consists of three lines with the syllable structure “five-seven-five.” National Haiku Poetry day celebrates the art form every April 18 — although we think it should be celebrated on May 7 (5-7)! Haikus typically revolve around nature, the passing of seasons, or ephemeral beauty.
At the risk of sounding like your high school English teacher, they rely more on images than metaphors. So there’s that.
They’re also very concise, due to their short length.