a. and sb. [? a. Fr. accidental, -el, 16th c. in Littré (cf. Pr. and Sp. accidental, It. accidentale), ad. med. or late L. accidentāl-is f. accidens, -ent-, sb. (see ACCIDENT); cf. occidentāl-is, parentāl-is. The regular L. form would probably have been accidentiāl-is f. accidentia, cf. essential, substantial.] Earliest occurrence in senses 3, 4.
A. adj.
I. Coming by chance, or on a chance occasion.
1. Happening by chance, undesignedly, or unexpectedly; produced by accident; fortuitous.
1578. Timme, Calvin on Gen., 84. As though all the crookedness of our disposition were not accidental.
1607. Topsell, Four-footed Beasts (1673), 267. Accidentall diseases be those that come by chance, as by surfetting, of cold, heat, and such like thing.
1653. Walton, Compl. Angler, i. 14. I made an accidental mention of it.
1765. Tucker, Lt. of Nat., II. 88. A man shoots at a rat in his yard, and kills a chicken which he did not intend, therefore we call this accidental.
1830. Lyell, Princ. Geol., I. 256. They are causes, therefore, as constant as the tides themselves, and, like them, depend on no temporary or accidental circumstances.
1883. Pall Mall G., 10 May, 3/1. The jury … deciding after some hesitation to find only accidental death.
2. Of or pertaining to a chance occasion or chance circumstances; casual, occasional.
1506. W. de Worde, Ordinary of Crysten Men, V. vii. [415]. The prayse of the good dedes done in the estate of mortall synne is a Joye accidentalle.
1533. Elyot, Castel of Helth (1541), 39. Some accidentall cause, as syckenes, or moche studye.
1603. Shaks., Meas. for M., III. i. 149. Oh fie, fie, fie: Thy sinn’s not accidentall, but a Trade.
1772. Pennant, Tours in Scotl. (1774), 341. Discovered by the accidental digging of peat.
1825. Waterton, Wanderings, I. i. 109. The accidental traveller … can merely mark the outlines of the path he has trodden.
1836. Todd, Cycl. An. & Ph., I. 497/1. Accidental Cartilage … the cartilaginous concretions … found in situations where they do not ordinarily exist.
II. Present by chance; non-essential.
3. Logic. Pertaining to logical accidents; not essential to the conception of a substance; not of the nature of its essence; non-essential.
1553–87. Foxe, A. & M., III. 251. Pendleton saith that the colour [of bread] was the earthly thing, and called it an accidental substance.
1628. T. Spencer, Logick, 277. The second, and third [figures] haue perfection essentiall, but not accidentall.
1788. Reid, Active Powers, I. i. 513. There are other relative notions that are not taken from accidental relations.
1846. Mill, Logic, I. vi § 2. 147. All properties, not of the essence of the thing, were called its accidents … and the propositions in which any of these were predicated of it were called Accidental Propositions.
4. Non-essential to the existence of a thing, not necessarily present, incidental, subsidiary.
c. 1386. Chaucer, Melibœus, 432. The cause accidental was hate; the cause material, ben the five woundes of thy doughter.
1670. Baxter, Cure of Ch. Div., 18. If in any integral or accidental point you think that you are wiser.
1750. Johnson, Rambler, No. 150. ¶ 4. Those accidental benefits which prudence may confer on every state.
1858. F. W. Robertson, Lect., ii. 148. Poetry is a something to which words are the accidental, not by any means the essential form.
5. Music. Accidental sharps, flats, naturals: signs of chromatic alteration, raising or lowering notes a tone or semitone, strictly so called only when they occur before particular notes, and not in the signature of the various keys.
1806. Callcott, Mus. Gram. Accidental Sharps and Flats only affect the Notes which they immediately precede.
1867. Macfarren, Harmony, i. 23. The employment in the minor of an accidental sharp or natural.
6. Optics. Accidental colors: complementary colors not actually caused by light, but due to subjective sensation.
1849. Mrs. Somerville, Connex. of Phys. Sc., § 19. 184. After looking steadily for a short time at a coloured object, such as a red wafer, on turning the eyes to a white substance, a green image of the wafer appears, which is called the accidental colour of red. All tints have their accidental colours.
7. Painting. Accidental lights: ‘secondary lights; effects of light other than ordinary daylight.’ Fairholt.
8. Perspective. Accidental point: ‘A point in the horizontal line, where lines parallel among themselves, though not perpendicular to the picture, do meet.’ Phillips, 1706.
¶ Also used adverbially.
1622. Rowlands, Good Newes, 13. Two canting rogues, that old consorts had bin, Did accidentall at an alehouse meet.
B. sb. a. A casual or subsidiary property, see A 3; b. Music. A sharp, flat, or natural, occurring not at the commencement of a piece of music in the signature, but before a particular note, see A 5; c. Painting. pl. ‘Those unusual effects of strong light and shade in a picture produced by the introduction of the representations of artificial light, such as those proceeding from a fire, candle, or the like.’ Fairholt.
1651. Baxter, Inf. Bapt., 31. You must distinguish between the Essentials and some Accidentals of the Jewish Church.
1726. Ayliffe, Parergon, 75. Altho’ a Custom introduc’d against the Substantials of an Appeal be not valid … yet a Custom may be introduc’d against the Accidentals of an Appeal.
1868. Ouseley, Harmony (1875), i. 6. The use of them [sharps, flats, etc.] both as accidentals and in the signature.
