Lumina is the plural form of the Latin word lumen, meaning "light" (in the sense of radiance, brightness). An alternate definition of lumen is "eye". In anatomy, a lumen, plural lumina, means opening or space. "Lumen" is used to describe the interior space of an anatomical structure, such as a blood vessel.
See Special:Whatlinkshere/Etymology:Lumina for a list of articles using this term.