Noun, pl. oculi
1. (Botany) An eye; a leaf bud. (biology-online.org)
2. A window or other opening that has an oval or circular shape (as of an eye). (wiktionary.org)
3. The organ of sight. (wordnetweb.princeton.edu)
4. The central boss of a volute. (Google Dictionary)
5. An opening at the apex of a dome. (Google Dictionary)
Word origin: From Latin oculus “eye”.