Claim: Massachusetts is one of 4 US commonwealths.
Evidence: Massachusetts -LSB- mæsəˈtʃuːsᵻts -RSB- or -LSB- ˌmæsəˈtʃuːzᵻts -RSB- ; officially the Commonwealth of Massachusetts , is the most populous state in the New England region of the northeastern United States.
Four states use the term commonwealth rather than state in their full official names.