[n] an item that is incidental
[n] (frequently plural) an expense not budgeted or not specified; "he requested reimbursement of $7 for incidental expenses"
[adj] not of prime or central importance; "nonessential to the integral meanings of poetry"- Pubs.MLA
[adj] (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 incident to a quick change"
[adj] following as a consequence; "an excessive growth of bureaucracy, with related problems"; "snags incidental to the changeover in management"