apse n.

"perigee of the moon, perihelion of a planet" (plural apsides), 1650s, from Latin apsis "arch, vault" (see apse).

"pertaining to the sense of touch," 1890, from Greek haptikos "able to come into contact with," from haptein "to fasten" (see apse).

"junction between two nerve cells," 1899, medical Latin, from Greek synapsis "conjunction," from or related to synaptein "to clasp, join together, tie or bind together, be connected with," from syn- "together" (see syn-) + haptein "to fasten" (see apse). Introduced by English physiologist Charles Sherrington (1857-1952), summarizing recent work by other neurologists, in the 1897 revision of Sir Michael Foster's "Textbook of Physiology;" the form of the coinage is owing to the suggestion of English classical scholar Arthur Woollgar Verral (1851-1912).