The regions beyond the gravitational influence of Earth encompassing interplanetary, interstellar, and intergalactic space. (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.
Use "deep space" in a sentence
"She had grown up in a spacefaring civilization, embedded in a family whose fortunes came from traveling the spaceways; she had been in deep space herself at thirteen."
"Designed as a deep space monitoring and scanning station, the mission profile of the MIDAS Array has evolved to include a unique function as a transgalactic communications relay."