quantum leap /ˈkwɒntəm liːp/noun 3verb 1forms 4 noun3 •The discontinuous change of the state of an electron in an atom or molecule from one energy level to another. •(figurative) An abrupt, extreme change.In the end, perhaps the practice of prayer effects a quantum leap of its own kind. It takes us, spontaneously and unexplainably, into the realm of spiritual energy. — 2001 •(nonstandard, figurative) A large, massive, significant change.A GIANT LEAP FORWARD Humanity is about to face a quantum leap forward. […] — 1995 verb1 •(slang) To manifest, to forward the reality of. formsquantum leaped · quantum leapt · quantum leaping · quantum leaps