Definitions

1. adjective

relating to or denoting the threshold or point at which a particular process or change occurs

“The luminal stage of cellular development is crucial for its growth.”

2. noun

a substance that fluoresces under ultraviolet light

“The researcher studied the luminal properties of a newly discovered molecule.”

3. noun

a region or layer of fluid or tissue at the boundary of two other substances

“The doctor examined the luminal space of the patient’s digestive system.”