giant molecular cloud

A cloud of molecular hydrogen typically located in the arm of a spiral galaxy, believed to be an area of active star formation. Protostars are located in the densest regions of such clouds. See more at protostar.

Nearby words

  1. giant hogweed,
  2. giant hornet,
  3. giant impact theory,
  4. giant kelp,
  5. giant killer,
  6. giant otter,
  7. giant panda,
  8. giant peacock moth,
  9. giant petrel,
  10. giant planet

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.