bye bye

WordReference Random House Learner's Dictionary of American English © 2025

bye-bye /interj. ˈbaɪˈbaɪ; n., adv. ˈbaɪˌbaɪ/   interj. 

1. Informal Terms, Slang Terms good-bye.

n. [uncountable]

2. Baby Talk. sleep.

adv., Idiom.

3. Slang Terms go bye-bye, Baby Talk. to leave;
   depart;
   go out:
   Let's put on our jackets; it's time to go bye-bye.

WordReference Random House Learner's Dictionary of American English © 2025

bye¹ /baɪ/   n. [countable] Also, by.

1. Sport a secondary matter.

Idioms

2. Idioms by the bye, by the way;
   incidentally.

bye² or by /baɪ/   interj. 

1. good-bye.

WordReference Random House Unabridged Dictionary of American English © 2025

bye-bye  (interj. bī′bī′;n., adv. bī′bī′), interj. 

1. Informal Terms, Slang Terms good-bye.

n. 

2. [Baby Talk.] sleep.

adv. 

3. Slang Terms go bye-bye, [Baby Talk.]
   • to leave;
     depart;
     go out.
   • to go to sleep;
     go to bed.

• apparently origin, originally nursery phrase used to lull a child to sleep, later construed as reduplicative form of by², short for good-bye 1700–10

WordReference Random House Unabridged Dictionary of American English © 2025

bye¹  (bī), n. 

Also, by. 
1. Sport in a tournament, the preferential status of a player or team not paired with a competitor in an early round and thus automatically advanced to play in the next round:
   The top three seeded players received byes in the first round.
2. Sport [Golf.] the holes of a stipulated course still unplayed after the match is finished.
3. Sport [Cricket.] a run made on a ball not struck by the batsman.
4. something subsidiary, secondary, or out of the way.
5. Idioms by the bye, by the way;
   incidentally:
   By
   the bye, how do you spell your name? Also, by the by. 

adj. 

6. by^1.

• variant spelling, spelled of by¹ in its noun, nominal sense "side way'' 1710–20

bye²  (bī), interj. 

1. by^2.

bye-, 

1. var. of by-:
   bye-election.

Collins Concise English Dictionary © HarperCollins Publishers::

bye / baɪ/ noun

1. the situation in which a player or team in an eliminatory contest wins a preliminary round by virtue of having no opponent
2. one or more holes of a stipulated course that are left unplayed after the match has been decided
3. a run scored off a ball not struck by the batter: allotted to the team as an extra and not to the individual batter
4. something incidental or secondary
5. by the bye ⇒ incidentally; by the way: used as a sentence connector

Etymology: 16th Century: a variant of by

bye, bye-bye sentence_substitute

1. goodbye