apsis
|ap-sis|
/ˈæpsɪs/
orbit extreme point
Etymology
'apsis' originates from Latin (borrowed from Greek 'ἁψίς' / 'hapsís'), where the Greek root meant 'arch' or 'loop' (a curved or hooked form).
'apsis' passed through Medieval/Late Latin (as 'apsis') and entered English via ecclesiastical and scientific Latin; over time the term was retained in technical contexts and became the modern English 'apsis'.
Initially it referred to an 'arch' or 'apse' in architecture; over time the word became specialized in astronomy to mean the extreme point of an orbit (closest or farthest approach).
Meanings by Part of Speech
Noun 1
either of the two extreme points in an orbit at the greatest or least distance from the central body (collectively referenced as periapsis and apoapsis).
An apsis is the point in an orbit where a satellite is farthest from or nearest to the body it orbits.
Synonyms
Noun 2
(archaic/architectural) A term historically used to refer to an apse or an arched/curved recess in a building.
In older architectural descriptions, 'apsis' was sometimes used to mean the church's apse.
Synonyms
Last updated: 2025/09/28 18:12