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n. pl. ap·si·des (-sĭ-dēz′)
1. Architecture An apse.
2. Astronomy The point of greatest or least distance of the orbit of a celestial body from the center of mass of the system.

[Late Latin, from Latin, arch, vault, from Greek hapsis, from haptein, to fasten.]


n, pl apsides (æpˈsaɪdiːz; ˈæpsɪˌdiːz)
1. (Astronomy) Also called: apse either of two points lying at the extremities of an eccentric orbit of a planet, satellite, etc, such as the aphelion and perihelion of a planet or the apogee and perigee of the moon. The line of apsides connects two such points and is the principal axis of the orbit
2. (Architecture) another name for apse1
[C17: via Latin from Greek; see apse]
apsidal adj


(ˈæp sɪs)

n., pl. -si•des (-sɪˌdiz)
1. either of the two points farthest or nearest the center of attraction in an eccentric astronomical orbit.
[1595–1605; < Latin < Greek hapsís (felloe of) a wheel, arch, vault, orig., fastening, derivative (of háptein to fasten]


- The extreme point of an orbit.
See also related terms for orbit.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.apsis - a domed or vaulted recess or projection on a building especially the east end of a churchapsis - a domed or vaulted recess or projection on a building especially the east end of a church; usually contains the altar
church building, church - a place for public (especially Christian) worship; "the church was empty"
niche, recess - an enclosure that is set back or indented
tribune - the apse of a Christian church that contains the bishop's throne
References in classic literature ?
This is in letters of gold around the apsis of a mosaic group at the side of the 'scala santa', church of St.
lactuca orientalis or Scariola Orientalis , rosemary, apsis are also among the famous herbs and plants in the region.
Advanced Sterilization Products (ASP), a leading global infection prevention solution provider, announced today the acquisition by its French affiliate, Apsis S.
Deals include: Barcelona from pounds 199 per person, including return scheduled flights from Heathrow or Gatwick and two nights at the four-star Apsis Atrium Palace hotel; Venice (pictured) from pounds 199 per person including scheduled flights from Gatwick and two nights at the three-star Best Western Montecarlo; and Paris from pounds 195 per person, including scheduled flights from Heathrow and two nights at the three-star Le Patio St Antoine hotel.
Two nights at the three-star Apsis Areanea Hotel costs from pounds 184 with flights from Gatwick during January.
The Sanctuary is paved with marble; and at the end of the apsis is another grand altar [St Andrew's altar], beautifully carved in Caen stone by Carao [sic.
Sogitec's Electronics Division produces the Apogee-3 realtime image generator, Apsis (designed to learn specific procedures for operating the Mirage 2000-5 pilot-system interface, the Bass intervention planning system, CMS2000 which is a computerised maintenance management system, a variety of G-seats, the Saxo support tool to design and produce training materials and multimedia applications for tutorial teaching, Sind-bad for the generation of 3-dimensional terrain databases and a Trigat-LR trainer.