Bible Encyclopedias
Apse (Mechanics)

1911 Encyclopedia Britannica

And APSIDES, in mechanics, either of the two points of an orbit which are nearest to and farthest from the centre of motion. They are called the lower or nearer, and the higher or more distant apsides respectively. The "line of apsides" is that which joins them, forming the major axis of the orbit.

Bibliography Information
Chisholm, Hugh, General Editor. Entry for 'Apse (Mechanics)'. 1911 Encyclopedia Britanica. https://www.studylight.org/​encyclopedias/​eng/​bri/​a/apse-mechanics.html. 1910.