1. multiplied by forty; forty times as great or as many

1. by forty times; to a degree forty times as great

Examples

• The investment increased fortyfold over the past decade.
• Production has grown fortyfold since the factory expanded.
• A fortyfold return on investment is exceptional.
• The population increased fortyfold in just fifty years.
• The company's revenue grew fortyfold after the merger.
• He received a fortyfold blessing for his generosity.