Definition of "hydrosphere" [hy•dro•sphere]

• The waters of the earth's surface as distinguished from those of the lithosphere and the atmosphere. (noun)
• The water vapor in the earth's atmosphere. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "GEOG 108: Introduction to Physical Geography I - A first year course dealing with the study of the Earth's atmosphere, biosphere and hydrosphere."
• "While admitting that the idea remained one of the greatest uncertainties in Mars research, they added that: "Our findings lend credence to the hypothesis that an ocean formed on early Mars as part of a global and active hydrosphere.""
• "She did not recall if there was a debate on evolution and creationism, nor did she recall mention of hydrosphere theory or water canopies."