I. ˌin(t)-sə-ˈden-t ə l adjective
Date: 1644
1.
a. : being likely to ensue as a chance or minor consequence
social obligations incidental to the job
b. : minor 1
2. : occurring merely by chance or without intention or calculation
II. noun
Date: 1707
1. plural : minor items (as of expense) that are not particularized
2. : something that is incidental