Math.
a topological space in which, for every point and a closed set not containing the point, there is a continuous function that has value 0 at the given point and value 1 at each point in the closed set.
COMPLETELY REGULAR SPACE
Meaning of COMPLETELY REGULAR SPACE in English
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012