The adjective accidental means unintentional or happening by chance.
The adjective incidental means secondary or nonessential. It often refers to something that occurs in connection with a more important activity or event.
- According to the National Safety Council, there were 600 accidental shooting deaths in the United States in 2009.
- In murder trials, the killer's motivation is thoroughly explored, whereas the type of weapon he used is often treated as an incidental detail.
(a) When you travel on business, _____ expenses are items such as local transportation, telephone calls, tips, and laundry.
(b) _____ fires are more likely to start in the kitchen than in any other room in the house.