1 one of the two large, heavy stones used in an old-fashioned mill for grinding grain.
az: dəyirman daşı
ru: жёрнов
2 (usually with round one’s/the neck) something that is a heavy burden or responsibility, and prevents easy progress: He regarded his brother as a millstone round his neck.
az: yük, ağırlıq
ru: камень на (чьей-л.) шее