ˌbig ˈbang ˌtheory BrE AmE noun
the big bang theory the idea that the universe began with a single large explosion (the ‘big bang’), and that the pieces are still flying apart ⇨ steady state theory
BIG BANG THEORY
Meaning of BIG BANG THEORY in English
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012