Final answer:
Laissez-faire in late 1800s US business refers to a 'let it be' policy with minimal government intervention. It was predominant during industrialization but led to increased regulation to protect citizens and maintain fair competition.
Step-by-step explanation:
The term Laissez-Faire when referring to business in the late 1800s in the United States, signifies a policy or attitude of letting things take their own course, without interfering. It stands for a political system with minimal governmental intervention in economic affairs, the 'let it be' approach.
This economic philosophy was predominant during the widespread industrialization of the U.S., where businesses operated almost free of government regulation. However, as it led to monopolies and poor working conditions, it prompted the government, with leaders like President Theodore Roosevelt, to establish regulations in order to protect competition and the welfare of the citizens.