apsis

noun

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ap·sis | \ ˈap-səs

plural apsides\ ˈap-sə-ˌdēz

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

2 : apse sense 2

Examples of apsis in a Sentence

Recent Examples on the Web Each term is sometimes called an apsis, which refers to the nearest or farthest point between a celestial body and its host. — NBC News, 5 Jan. 2022

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

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