What is the meaning of conglomerate?

noun

• A composite rock made up of particles of varying size.
  • synonyms: pudding stone
• A group of diverse companies under common ownership and run as a single organization.
  • synonyms: empire

verb

• Collect or gather.
  • usage: "Journals are accumulating in my office"; "The work keeps piling up"
  • synonyms: accumulate, cumulate, pile up, gather, amass

adjective

• Composed of heterogeneous elements gathered into a mass.
  • usage: "the conglomerate peoples of New England"