Definitions for "Cosmological constant"
A term in the equations of general relativity that represents a repulsive force in the universe. The cosmological constant is usually assumed to be zero.
a modification of general relativity's original equations, allowing for a static universe; interpretable as a constant energy density of the vacuum.
A term added to the field equations by Einstein in order to allow solutions in which the universe was static; that is, neither expanding nor contracting. Although the need for the term disappeared when it was discovered that the universe is expanding, the cosmological constant is retained in the field equations by modern cosmologists, but is usually assigned the value zero.