apsis
/ˈæpsɪs/
noun
- In astronomy, either of the two points in an orbit that are closest to or farthest from the body being orbited (e.g., the sun or a planet).
- The spacecraft will reach its apsis, the point closest to Mars, tomorrow.
- The moon's apsis changes slightly over time due to gravitational pulls.
- Astronomers calculated the apsis of the comet's orbit to predict its return.
- In architecture, a semicircular or polygonal recess in a building, often at the end of a church or temple, usually with a domed roof.
- Visitors admired the apsis of the cathedral, where the altar stood.
- The ancient church had a beautiful apsis decorated with gold mosaics.
- The architect designed an apsis at the eastern end of the chapel.