n.
Pronunciation: ' ap-s ə s
Function: noun
Inflected Form: plural ap · si · des \ -s ə - ˌ d ē z \
Etymology: New Latin apsid-, apsis, from Latin, arch, orbit, from Greek hapsid-, hapsis, from haptein to fasten
Date: 1658
1 : the point in an astronomical orbit at which the distance of the body from the center of attraction is either greatest or least
2 : APSE 2