According to "Kinginzuroku" (Gold & Silver catalog), originally Chogin written as 鋌銀 meant silver bars, later the character was changed to 挺銀, then to 丁銀, although all were pronounced as Chogin.
丁銀という名称は『金銀図録』の記述によれば棒状の銀塊の意味である鋌銀（ちょうぎん）が挺銀（ちょうぎん）を経て変化したものとされる。