We found 6 dictionaries that define the word thatll be the day:

General (4 matching dictionaries)

1. that'll be the day: Merriam-Webster
2. that'll be the day: Cambridge Advanced Learner's Dictionary
3. that'll be the day: Wiktionary
4. That'll Be The Day (film), That'll Be the Day, That'll Be the Day (album), That'll Be the Day (film): Wikipedia, the Free Encyclopedia

Miscellaneous (1 matching dictionary)

5. That'll be the day, that'll be the day: Idioms

Slang (1 matching dictionary)

6. That'll be the Day: Urban Dictionary

▸ Words similar to thatll be the day ▸ Usage examples for thatll be the day ▸ Idioms related to thatll be the day ▸ Wikipedia articles (New!) ▸ Words that often appear near thatll be the day ▸ Rhymes of thatll be the day ▸ Invented words related to thatll be the day