(topology) A regular space with the additional property that for every disjoint pair of closed sets in that space, there is a disjoint pair of open sets which contain the closed sets, respectively.

plural of normal subgroup

(technology) for LCD to be opaque and thus black when voltage is not applied to a pixel electrode and transparent and thus white when voltage is applied.

(technology) for LCD to be transparent and thus white when voltage is not applied to a pixel electrode and opaque and thus black when voltage is applied.

(photography) A lens which produces an image similar in detail and angular perspective to the view produced by the human eye, as distinct from a wide-angle lens or a telephoto lens.

(economics) a good for which demand increases when income increases and falls when income decreases but price remains constant, i.e. with a positive income elasticity of demand.

The study of the microscopic structure of living tissue (histology) that is in good health (as opposed to pathological histology which studies that of diseased tissue).

plural of normal pause

(statistics) Any of a family of continuous probability distributions such that the probability density function is the Gaussian function

(group theory) A subgroup H of a group G that is invariant under conjugation; that is, for all elements h of H and for all elements g in G, the element ghg⁻¹ is in H.