- Incidental In`ci*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.
I treat either or incidentally of colors. --Boyle. [1913 Webster]
The Collaborative International Dictionary of English. 2000.