Meaning of the word "all day" in English

What does "all day" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

all day

US /ɔːl deɪ/
UK /ɔːl deɪ/

Phrase

throughout the entire day

Example:
I've been working on this project all day.
The store is open all day, from morning till evening.