Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This

American Heritage Dictionary - Cite This Source - Share This

ac·ci·den·tal       (āk'sĭ-děn'tl)  Pronunciation Key  adj.   Occurring unexpectedly, unintentionally, or by chance. Music Of or relating to an accidental. n.   A property, factor, or attribute that is not essential. Music Any of various signs that indicate the alteration of a note by one or two semitones or the cancellation of a previous sign. A note that has been marked with such a sign. ac'ci·den'tal·ly, ac'ci·dent'ly adv., ac'ci·den'tal·ness n. Synonyms: These adjectives apply to what happens unintentionally. Accidental primarily refers to what occurs by chance: an accidental meeting. It can also mean subordinate or nonessential: "Poetry is something to which words are the accidental, not by any means the essential form" (Frederick W. Robertson). Fortuitous stresses chance even more strongly: "the happy combination of fortuitous circumstances" (Sir Walter Scott). Contingent describes what is possible but uncertain because of unforeseen or uncontrollable factors: "The results of confession were not contingent, they were certain" (George Eliot). Incidental refers to a minor or unanticipated result or accompaniment: "There is scarcely any practice which is so corrupt as not to produce some incidental good" (Enoch Mellor). Adventitious applies to something acquired or added externally, sometimes by accident or chance: "The court tries to understand 'whether the young man's misconduct was adventitious or the result of some serious flaw in his character'" (Harry F. Rosenthal).

WordNet - Cite This Source - Share This

accidental
adjective
1.	happening by chance or unexpectedly or unintentionally ; "with an inadvertent gesture she swept the vase off the table"; "accidental poisoning"; "an accidental shooting"
noun
1.	a musical notation that makes a note sharp or flat or natural although that is not part of the key signature

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Accidental

Ac`ci*den"tal\, a. [Cf. F. accidentel, earlier accidental.]

1. Happening by chance, or unexpectedly; taking place not according to the usual course of things; casual; fortuitous; as, an accidental visit.

2. Nonessential; not necessary belonging; incidental; as, are accidental to a play.

Accidental chords (Mus.), those which contain one or more tones foreign to their proper harmony.

Accidental colors (Opt.), colors depending on the hypersensibility of the retina of the eye for complementary colors. They are purely subjective sensations of color which often result from the contemplation of actually colored bodies.

Accidental point (Persp.), the point in which a right line, drawn from the eye, parallel to a given right line, cuts the perspective plane; so called to distinguish it from the principal point, or point of view, where a line drawn from the eye perpendicular to the perspective plane meets this plane.

Accidental lights (Paint.), secondary lights; effects of light other than ordinary daylight, such as the rays of the sun darting through a cloud, or between the leaves of trees; the effect of moonlight, candlelight, or burning bodies. --Fairholt.

Syn: Casual; fortuitous; contingent; occasional; adventitious.

Usage: Accidental, Incidental, Casual, Fortuitous, Contingent. We speak of a thing as accidental when it falls out as by chance, and not in the regular course of things; as, an accidental meeting, an accidental advantage, etc. We call a thing incidental when it falls, as it were, into some regular course of things, but is secondary, and forms no essential part thereof; as, an incremental remark, an incidental evil, an incidental benefit. We speak of a thing as casual, when it falls out or happens, as it were, by mere chance, without being prearranged or premeditated; as, a casual remark or encounter; a casual observer. An idea of the unimportant is attached to what is casual. Fortuitous is applied to what occurs without any known cause, and in opposition to what has been foreseen; as, a fortuitous concourse of atoms. We call a thing contingent when it is such that, considered in itself, it may or may not happen, but is dependent for its existence on something else; as, the time of my coming will be contingent on intelligence yet to be received.

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Accidental

Ac`ci*den"tal\, n. 1. A property which is not essential; a nonessential; anything happening accidentally.

He conceived it just that accidentals . . . should sink with the substance of the accusation. --Fuller.

2. pl. (Paint.) 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.

3. (Mus.) A sharp, flat, or natural, occurring not at the commencement of a piece of music as the signature, but before a particular note.