(mathematics) A collection Ï„ of subsets of a set X such that the empty set and X are both members of Ï„ and Ï„ is closed under arbitrary unions and finiteintersections.
(technology) The properties of a particular technological embodiment that are not affected by differences in the physical layout or form of its application.
(topography) The topographical study of geographic locations or given places in relation to its history.
(dated) The art of, or method for, assisting the memory by associating the thing or subject to be remembered with some place.