Wiktionary
n. (context mathematics English) Any topological space which cannot be written as the disjoint union of two or more nonempty open spaces.
Wikipedia
In topology and related branches of mathematics, a connected space is a topological space that cannot be represented as the union of two or more disjoint nonempty open subsets. Connectedness is one of the principal topological properties that are used to distinguish topological spaces. A stronger notion is that of a path-connected space, which is a space where any two points can be joined by a path.
A subset of a topological space X is a connected set if it is a connected space when viewed as a subspace of X.
An example of a space that is not connected is a plane with an infinite line deleted from it. Other examples of disconnected spaces (that is, spaces which are not connected) include the plane with an annulus removed, as well as the union of two disjoint closed disks, where all examples of this paragraph bear the subspace topology induced by two-dimensional Euclidean space.
Usage examples of "connected space".
Once used they were gone for good, coherence destroyed by the process that allowed them to teleport the state of a single bit between points in causally connected space-time.