bye-bye
exclamation
[ bʌɪˈbʌɪ ]
• another way of saying goodbye.
Origin:
early 18th century: child's reduplication.
bye-byes
noun
• a child's word for sleep.
• "definitely not the book to read before bye-byes"
Origin:
mid 19th century: from the sound bye-bye, long used as a refrain in lullabies.
