semimajor axis


semi·​ma·​jor axis ˌse-mē-ˈmā-jər- How to pronounce semimajor axis (audio)
: one half of the major axis of an ellipse (such as that formed by the orbit of a planet)

Example Sentences

Recent Examples on the Web The uncertainty in its semimajor axis (the radius of its orbit at its two most separated points) is just six meters out of a total length of 168,505,699.049 kilometers. Dante S. Lauretta, Scientific American, 1 Aug. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'semimajor axis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1818, in the meaning defined above

Time Traveler
The first known use of semimajor axis was in 1818

Dictionary Entries Near semimajor axis

Cite this Entry

“Semimajor axis.” Dictionary, Merriam-Webster, Accessed 26 Mar. 2023.

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