1) The repeating part of a rock, pop, or country song that the main verses lead up and return to, usually the section where the title of the song is sung.
2) A common electronic effect used for guitar and other audio which takes a copy of the original audio signal, delays it by a number of milliseconds, and plays it back with the original signal, resulting in a warmer, spacious sound.
3) An organized group of singers
2) I bought a chorus stompbox at the music store for $50.
3) He missed chorus practice today.
"Why doesn't Stairway have a chorus?"
"The chorus of any Nickelback song is capable of murder most foul."