An independent reference system of positioning points in space

(mathematics) A half space that does not include the plane that bounds it

Any assemblage of equipment used to generate, store and distribute electrical power on board a satellite or spacecraft

Any of a system of coordinates by which a point is located in space by its distance from a pole, the angle between the polar axis and its radius vector, and its longitude

(topology, Britain) Alternative spelling of Seifert fiber space

(topology, chiefly US) A fiber bundle whose fiber is the circle and whose base space is a two-dimensional orbifold

(topology, Britain) Alternative spelling of Seifert fiber space

(topology, US) Alternative spelling of Seifert fiber space

The process, made possible by technological innovations in transportation and communication, by which distant places are brought closer together in terms of the time taken to travel (or send messages) between them.

(mathematics) A topological space that has precisely one nontrivial homotopy group.