A shortened nickname of the Japanese Anime "Danshi Koukousei no Nichijou," which is an anime about the daily lives of a bunch of guys, hence the "bro." It is not to be confused with the anime "Nichijou," which is an anime about the daily lives of a bunch of girls.

One who enjoys the Japanese anime show, "Nichijou," which is a show that follows the lives of a group of high school students and their school. Various oddities and absurdities abound, such as a robotic girl made by an eight-year-old scientist, a boy who rides a goat to school with his butler, a girl who can procure various guns out of thin air, a cat that can speak and a principal who has wrestled a deer. Despite its bizarre settings and characters, the students still lead normal lives.

The term was made by 4chan's /a/