1
: the Roman god of war compare ares
2
: the planet fourth in order from the sun and conspicuous for its red color see Planets Table

Word History

Etymology

Latin Mart-, Mars

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of Mars was in the 14th century

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Cite this Entry

“Mars.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Mars. Accessed 9 Sep. 2025.

Kids Definition

Mars

noun
: the planet fourth in order from the sun see planet

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