millstone (plural millstones)
- A large round stone used for grinding grain.
- (geology) A coarse-grained sandstone used for making such stones; millstone grit.
- (figurative) Often in a millstone round one's neck (referring to Matthew 18:6 in the Bible): a heavy responsibility that is difficult to bear#Verb|bear.
- Paying the mortgage every month is a millstone round their necks.
- French: meulière
- German: Klotz am Bein
- A nuclear power station near Waterford, Connecticut, USA.
- An unincorporated community in Mercer County, New Jersey.
- A borough in Somerset County, New Jersey.
- The Millstone River, a tributary of the Raritan River in New Jersey.