ˈ ̷ ̷ˌ ̷ ̷ noun
Etymology: Middle English mulleston, mylneston, from mulle, mylne, mille mill + ston stone
1. : either of two circular stones often built up of several pieces and used for grinding grain or other substance fed through a center hole in the upper stone — see millrind , mill spindle
2. : buhrstone 1
3.
a. : something that grinds or crushes
caught between the millstones of high prices and low wages
b. : a heavy or crushing burden (as of guilt)