IncindentalIn`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.