\In`cin*den"tal\, a.
Happening, as an occasional event, without regularity; coming
without design; casual; accidental; hence, not of prime
concern; subordinate; collateral; as, an incidental
conversation; an incidental occurrence; incidental expenses.

      By some, religious duties . . . appear to be regarded .
      . . as an incidental business.           --Rogers.

Syn: Accidental; casual; fortuitous; contingent; chance;
     collateral. See {Accidental}. -- {In`cen*den"tal*ly},
     adv. -- {In`cen*den"tal*ness}, n.

           I treat either or incidentally of colors. --Boyle.