Abstract: The “conviction” definition is one of the most misunderstood and odious provisions in our country’s immigration statute. The “conviction” term is a misnomer because it includes criminal dispositions that are often not considered convictions at all. Despite its perplexing definition, “convictions” are frequently used as markers for removal. For example, in FY2017, Immigration and Customs Enforcement (“ICE”) apprehended 143,470 individuals within the interior of the United States and ninety-two percent of those individuals had a criminal conviction, arrest, or an outstanding removal order. In FY2016, ICE’s apprehension totals likewise showed that ninety-two percent of individuals arrested by ICE had a criminal conviction. The purpose of this short article is to explain immigration law’s enigmatic “conviction” definition, its nefarious history, and current efforts to challenge the definition’s interpretation. In so doing, the article draws on my prior scholarship, which — along with a seminal article by immigration scholar Jason Cade — became the blueprint for challenging the “conviction” definition in federal court.