(a.) Happening by chance, or unexpectedly; taking place not according to the usual course of things; casual; fortuitous; as, an accidental visit.
(a.) Nonessential; not necessary belonging; incidental; as, are accidental to a play.
(n.) A property which is not essential; a nonessential; anything happening accidentally.
(n.) Those fortuitous effects produced by luminous rays falling on certain objects so that some parts stand forth in abnormal brightness and other parts are cast into a deep shadow.
(n.) A sharp, flat, or natural, occurring not at the commencement of a piece of music as the signature, but before a particular note.