regular space
topological space in which a point and a closed set are, if disjoint, separable by neighborhoods
en-US/ˈɹɛɡjəlɚ ˈspeɪs/
en-GB/ˈɹɛɡjuːlə ˈspeɪs/
topological space in which a point and a closed set are, if disjoint, separable by neighborhoods