late 14c., "flow of rhythm in prose or verse," from French cadence, from Old Italian cadenza "conclusion of a movement in music," literally "a falling," from Vulgar Latin *cadentia, from neuter plural of Latin cadens, present participle of cadere "to fall" (from PIE root *kad- "to fall"). A doublet of chance (n.).
The notion is of a "fall" in the voice in reading aloud or speaking, as at the end of a sentence, also the rising and falling in modulation of tones in reciting. Later (1590s) extended to music, in reference to a sequence of chords expressing conclusion at the end of a phrase and resolving to the key in which the piece was written. Also the measure or beat of any rhythmic movement (c. 1600). In 16c., sometimes used literally for "an act of falling." Related: Cadential.
It forms all or part of: accident; cadaver; cadence; caducous; cascade; case (n.1); casual; casualty; casuist; casus belli; chance; cheat; chute (n.1); coincide; decadence; decay; deciduous; escheat; incident; occasion; occident; recidivist.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sad- "to fall down;" Latin casus "a chance, occasion, opportunity; accident, mishap," literally "a falling," cadere "to fall, sink, settle down, decline, perish;" Armenian chacnum "to fall, become low;" perhaps also Middle Irish casar "hail, lightning."
"nothing," 1957; "insignificant person," 1933, from use of Zilch as a generic comical-sounding surname for an insignificant person (especially Joe Zilch). There was a Mr. Zilch (1931), comic character in the magazine "Ballyhoo," and the use perhaps originated c. 1922 in U.S. college or theater slang. Probably a nonsense syllable, suggestive of the end of the alphabet, but Zilch is an actual German surname of Slavic origin.
The [Cadence] agency aims to have each album cover actually promote the record, on the theory that "the day of pretty, boffy, zoomy and zingy covers for the sake of zilch is no more." [Billboard, Oct. 28, 1957]
"music form featuring flatted thirds and sevenths," possibly c. 1895 (though officially 1912, in W.C. Handy's "Memphis Blues"). Blue note "minor interval where a major would be expected" is attested from 1919, and at first was suspected as a source of the term.
I am under the impression that these terms [blue note, blue chord] were contemporary with, if they did not precede and foreshadow, the period of our innumerable musical 'Blues.' What the uninitiated tried to define by that homely appellation was, perhaps, an indistinct association of the minor mode and dyspeptic intonation with poor digestion; in reality, it is the advent in popular music of something which the textbooks call ambiguous chords, altered notes, extraneous modulation, and deceptive cadence. [Carl Engel, "Jazz: A Musical Discussion," The Atlantic Monthly, August 1922]