millstone

One of a pair of cylindrical stones used in a mill for grinding grain.

A source of worry or distress.

An obstacle to success. synonym: burden.

One of a pair of cylindrical stones used in a mill for grinding grain.

One of two circular stones used for grinding grain or other substance in a mill{1}.

a hard and coarse, gritty sandstone, dividing the Carboniferous from the Subcarboniferous strata. See Farewell rock, under Farewell, a., and Chart of Geology.

to see into or through a difficult matter.

A large round stone used for grinding grain.