For 'mura,' there are theories such as that the origin is Nobushige's older sister Muramatsu, head of the Date family Tsunamura DATE, whom Nobushige's descendants served, or the yoto (a mysterious sword) Muramasa, which was alleged to curse the Tokugawa family.
「村」については信繁の姉の村松や、信繁の子孫が仕えた伊達家当主の伊達綱村、徳川家を呪ったとされる妖刀村正に由来しているとする説などがある。