mass is on the Basic English 850 List.
material - mass - may

Pronunciation

change

Singular
mass

Plural
masses

  1. A measure of how much material is in something.
    The Earth has much more mass than the moon.
    The spacesuit weighed 75 pounds on Earth but here in outer space it weighed nothing, although its mass was exactly the same.
  2. Much material.
    A mass of dirty branches stopped the river.
  3. A Christian ceremony in memory of the Last Supper.
    He goes to mass every Sunday.
  4. A crowd of people.
    A mass of protesters gathered at city hall.