ap·​sis | \ ˈap-səs How to pronounce apsis (audio) \
plural apsides\ ˈap-​sə-​ˌdēz How to pronounce apsides (audio) \

Definition of apsis

1 : the point in an astronomical orbit at which the distance of the body from the center of attraction is either greatest or least

First Known Use of apsis

1601, in the meaning defined at sense 1

History and Etymology for apsis

borrowed from Medieval Latin apsīs, apsīda "arc, vault," going back to Latin apsīd-, apsīs (also hapsīs, absīs) "arc described by a planet, segment of a circle," borrowed from Greek hapsīd-, hapsís (Ionic apsís) "loop, mesh, rim of a wheel, wheel, disk, segment cut off by a rainbow, arch, vault," from ap-s-, stem in noun derivation of háptein "to fasten," háptesthai "to fasten oneself to, grasp" + -īd-, -īs, noun suffix — more at haptics

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The first known use of apsis was in 1601

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Cite this Entry

“Apsis.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/apsis. Accessed 26 January 2020.

More from Merriam-Webster on apsis

Britannica.com: Encyclopedia article about apsis

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to express in a more acceptable way

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