Ⅰ.
mass UK US /mæs/ adjective [before noun]
► having an effect on or involving a large number of people: »
There have been two decades of mass unemployment.
mass audience/appeal »A smaller company could produce a breakthrough product with mass appeal.
mass consumerism/consumption »The society that we live in now is so geared to spending and mass consumerism.
»a mass protest/rally/action
Ⅱ.
mass UK US /mæs/ noun
► [U] the amount of matter in any solid object or volume of liquid or gas: »
These activities help strengthen bones and increase their mass.
Financial and business terms. 2012.