Definition of incidental

• (frequently plural) an expense not budgeted or not specified; "he requested reimbursement of $7 for incidental expenses"
• an item that is incidental
• (sometimes followed by `to) minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence; "incidental expenses"; "the road will bring other incidental advantages"; "extra duties incidental to the job"; "labor problems incidental to a rapid expansion"; "confusion incidental to a quick change"