Definition of mass
- Sunday masses held at three different hours
- Bach's Mass in B Minor
First Known Use: before 12th centurySee Words from the same year
A large crowd of demonstrators massed outside the courthouse.
Clouds were massing on the horizon.
The generals massed their troops.
Television is a mass medium.
: to form or gather into a large group
: involving, affecting, or designed for many people
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