ˈapsəd ə l adjective
Etymology: Latin apsid-, apsis + English -al
1. : of or relating to the apsides of an orbit
apsidal motion
2.
[Medieval Latin apsid-, apsis + English -al ]
: of or relating to the apse of a church
• ap·si·dal·ly -dəlē also -d ə lē adverb