Definition of "bye-bye" []

• Used to express farewell. (interjection)
• Informal Away. (adverb)
• Informal To bed; to sleep: "[Live Senate television is] a great way to go bye-bye. Pretty soon you're asleep” ( William Proxmire). (adverb)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Consider this, a day in the life of a typical feline sterilization extravaganza:I arrived at 11 a.m. on Sunday morning … just in time to see the coffee and doughnuts go bye-bye."
• "It goes all the way in the pipes, and then, it goes bye-bye forever."
• "Sasha, the other female "beast" this season is also safe, which means it's bye-bye Caitlynn, who danced an amazingly angst-y but mature Sonya Tayeh routine Wednesday."