Misspelling of en masse.

The output of a mass spectrometer

A direct action event in which bicycle riders travel through city streets as a group.

plural of critical mass

plural of mass murderer

sacring-bell

plural of mass spectrograph

(physics, analytical chemistry) A mass spectrometer

(psychology) The sociopsychological phenomenon in which a large group of people exhibit the same or similar hysterical symptoms simultaneously.

plural of point mass