What's the definition of business liability insurance?

This differs entirely based on your business and its circumstances:

• What do you sell?
  
• How many people do you employ, if any?
• Do you conduct business in multiple provinces?
  
• Do you conduct business in the United States, or elsewhere in the world?
  
• What coverage options do you want?
  
• How high will you set your policy limits?
  

All of those factors (and many others) affect the price you pay for your business liability insurance.