The Aryan Brotherhood is a neo-Nazi prison gang and an organized crime syndicate that is based in the United States and has an estimated 15,000–20,000 members both inside and outside prisons. The Southern Poverty Law Center (SPLC) has characterized it as "the nation's oldest major white supremacist prison gang and a national crime syndicate" while the Anti-Defamation League calls it the "oldest and most notorious racist prison gang in the United States". According to the Federal Bureau of Investigation (FBI), the Aryan Brotherhood makes up an extremely low percentage of the entire US prison population, but it is responsible for a disproportionately large number of prison murders.

A shamrock is a type of clover, used as a symbol of Ireland. Saint Patrick, one of Ireland's patron saints, is said to have used it as a metaphor for the Christian Holy Trinity. The name shamrock comes from Irish seamróg, which is the diminutive of the Irish word seamair and simply means "young clover".