semimajor axis

semi·​ma·​jor axis | \ ˌse-mē-ˈmā-jər- How to pronounce semimajor axis (audio) , ˌse-ˌmī-, -mi- \

Definition of semimajor axis

: one half of the major axis of an ellipse (such as that formed by the orbit of a planet)

First Known Use of semimajor axis

1818, in the meaning defined above

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The first known use of semimajor axis was in 1818

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semimagnetic controller

semimajor axis


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Cite this Entry

“Semimajor axis.” Dictionary, Merriam-Webster, Accessed 5 Dec. 2021.

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