will have been massing

• future perfect progressive

  future perfect progressive

  Used to describe a continuous action that will progress up until a designated point of completion in the future.

  of mass.
  mass

  noun

  a body of coherent matter, usually of indefinite shape and often of considerable size.

Related Words

• crowd
• group
• horde
• lot
• lump
• majority
• mob
• number
• piece
• pile
• throng