n.

1. the property of a body that causes it to have weight in a gravitational field
2. (often followed by `of') a large number or amount or extent;
   batch, deal, flock, good deal, great deal, hatful, heap, lot, mess, mickle, mint, muckle, peck, pile, plenty, pot, quite a little, raft, sight, slew, spate, stack, tidy sum, wad, whole lot, whole slew
   
   • a batch of letters
   • a deal of trouble
   • a lot of money
   • he made a mint on the stock market
   • it must have cost plenty
3. an ill-structured collection of similar things (objects or people)
4. (Roman Catholic Church and Protestant Churches) the celebration of the Eucharist;
   Mass
5. a body of matter without definite shape
   
   • a huge ice mass
6. the common people generally;
   multitude, masses, hoi polloi, people, the great unwashed
   
   • separate the warriors from the mass
   • power to the people
7. the property of something that is great in magnitude;
   bulk, volume
   
   • it is cheaper to buy it in bulk
   • he received a mass of correspondence
   • the volume of exports
8. a musical setting for a Mass;
   Mass
   
   • they played a Mass composed by Beethoven
9. a sequence of prayers constituting the Christian Eucharistic rite;
   Mass
   
   • the priest said Mass

v.

1. join together into a mass or collect or form a mass
   
   • Crowds were massing outside the palace

adj.

1. gathered or tending to gather into a mass or whole;
   aggregate, aggregated, aggregative
   
   • aggregate expenses include expenses of all divisions combined for the entire year
   • the aggregated amount of indebtedness