incidental in WordNet English dictionary

1. following or accompanying as a consequence
   "an excessive growth of bureaucracy, with attendant problems"; "snags incidental to the changeover in management"; "attendant circumstances"; "the period of tension and consequent need for military preparedness"; "the ensuant response to his appeal"; "the resultant savings were considerable"
   attendant  consequent  accompanying  concomitant  incidental  ensuant  resultant  sequent 
   
2. (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"
   incidental  incident 
   
3. not of prime or central importance
   "nonessential to the integral meanings of poetry"- Pubs.MLA
   incidental  nonessential 
   

1. an item that is incidental
   incidental 
   
2. (frequently plural) an expense not budgeted or not specified
   "he requested reimbursement of $7 for incidental expenses"
   incidental expense  incidental  minor expense