Meanings
Earlier call it half a day, first attested in 1838, meaning to leave before the working day was over.
How to pronounce "call it a day":
AU
To cease the activity for the day.
Example: "We have been at this for hours; let's call it a day and come back tomorrow when we are fresh."
To retire.
Example: "After suffering massive losses for three years in a row, the boss decided to call it a day, and sold his company."
Example Sentences
1
After working on the project for hours, we decided to call it a day and continue tomorrow.
2
The concert had been going on for hours, and the band decided to call it a day and end the show.
3
We were fishing, but when the fish stopped biting, we decided to call it a day and return home.