cosmic string

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of numerous very long and thin alterations or topological defects in space-time hypothesized to have resulted from the Big Bang and to have made possible the conglomeration of mass into large-scale structures such as galaxy clusters and the inhomogeneous distribution of matter in the universe.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A cosmically-scaled string of mass-energy left over from the big bang as a topological defect in spacetime.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (cosmology) a hypothetical one-dimensional subatomic particle having a concentration of energy and the dynamic properties of a flexible loop