Definition of big business in English English dictionary
commercial enterprises organized and financed on a scale large enough to influence social and political policies; "big business is growing so powerful it is difficult to regulate it effectively
Something that is big business is something which people spend a lot of money on, and which has become an important commercial activity. Sport has become big business. Commercial operations organized and financed on a large scale: clashes between labor and big business
Big business is business which involves very large companies and very large sums of money. Big business will never let petty nationalism get in the way of a good deal