A topological space fulfilling the T_2-axiom: i.e., any two points have disjoint neighborhoods. In the terminology of Alexandroff and Hopf, a T_2-space is called a Hausdorff space. A T_2-space is sometimes said to "have Hausdorff topology" or "be Hausdorff." An Etale space provides an example of a space that is not T_2.