What does chorus mean?

What does chorus mean?
A spoken definition of chorus.
Intro Sound:
Typewriter - Tamskp
Licensed under CC:BA 3.0
Outro Music:
Groove Groove - Kevin MacLeod (incompetech.com)
Licensed under CC:BA 3.0
Intro/Outro Photo:
The best days are not planned - Marcus Hansson
Licensed under CC-BY-2.0
Book Image:
Open Book template PSD - DougitDesign
Licensed under CC:BA 3.0
Text derived from:
en.wiktionary.o...
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