What does cacophony mean?

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From our dictionary:

ca•coph•o•ny

Pronunciation: (ku-kof'u-nE), [key]
n.,
pl. -nies.

1. harsh discordance of sound; dissonance: a cacophony of hoots, cackles, and wails.
2. a discordant and meaningless mixture of sounds: the cacophony produced by city traffic at midday.
3. Music.frequent use of discords of a harshness and relationship difficult to understand.