apsis.

/ap-sis/US // ˈæp sɪs //UK // (ˈæpsɪs) //

卫星导航仪,卫星导航

Definitions

1.
plural ap·si·des [ap-si-deez]. /ˈæp sɪˌdiz/.
- ›Astronomy. either of two points in an eccentric orbit, one farthest from the center of attraction, the other nearest to the center of attraction.
- ›Architecture. an apse.

The nave of the chapel is in tolerably good preservation, but the apsis has suffered severely from damp.
The tomb is in the wall, behind a range of pillars, which form a kind of open screen round the apsis.
But the choir and apsis were previously of a different æra from the rest of the edifice.
The seven-sided apsis with ambulatory, on which open out seven pentagonal radiating chapels.
Between the apsis and the nave stood the altar, or rather the common table, canopied by a baldachin supported by columns.