fenestella

fenestella [ˌfɛnɪˈstɛlə]

n pl -lae [-liː]

1. (Christianity / Ecclesiastical Terms) RC Church a small aperture in the front of an altar, containing relics

2. (Christianity / Ecclesiastical Terms) Ecclesiast a niche in the side wall of a chancel, in which the credence or piscina are set

3. (Fine Arts & Visual Arts / Architecture) Architect a small window or an opening in a wall

[from Latin: a little window, from fenestra window]

Thesaurus

Noun

1.

fenestella - oval or circular opening; to allow light into a dome or vault lunette opening - a vacant or unobstructed space that is man-made; "they left a small opening for the cat at the bottom of the door" vault - an arched brick or stone ceiling or roof