oculus
Concise Oxford English Dictionary © 2008 Oxford University Press:
oculus /ˈɒkjʊləs/
▶noun (pl. oculi /-lʌɪ, -liː/) Architecture
- 1 a circular window.
- 2 the central boss of a volute.
- 3 an opening at the apex of a dome.
– origin C19: from L., lit. ‘eye’.
'oculus' also found in these Oxford entries:

