Definition: A mix of discordant sounds; dissonance (Ex: the cacophony of car horns, police sirens, barking dogs of quotidian city life).
Part of Speech: noun
Pronunciations: kə.ˈkɒ.fə.ni
or, if you prefer the IPA: kuh-KAH-fuh-nee
Example: Perceived as cacophony by some, the shouts, calls, and laughter of the playground was euphony [beautiful sounds] to Señor Chang, who reminisced nostalgically on his childhood.
Background: cacophony is one of those challenge words (SAT, GRE, etc.) that you're bound to come across sooner or later in your studies; it's a useful word, and easy to remember. caco comes from the Greek, which means bad; we don't have too many common words in English with this root (cacodyl (a poisonous chemical) and caconym (an incorrect name for something) are two others), but the root phone is much more common; it means (you probably know this already) sound.