hagioscope

From hagio- (“saint”) +‎ -scope (“viewing instrument”).

hagioscope (plural hagioscopes)

1. (architecture) A small opening in an interior wall of a church, enabling those in the transept to view the high altar.

   Synonyms: leper's squint, lychnoscope, squint

   • 1886, Miss M. A. R. Tucker, “St. David's”, in Walford's Antiquarian: A Magazine & Bibliographical Review:

     It appears that Drs. Jones and Freeman account for the arch over the hagioscope at St. David's by saying, though without citing authorities, that there was a door there originally.

• oesophagic, œsophagic