✔ 最佳答案
I think it's just a label for a period of time. "Lunch break" should mean a certain amount of minutes. Like 30 or 60. And it means you get to use that time however you want. You can use it to eat, or sleep or read or talk on the phone or whatever. Where you eat your lunch is immaterial. If you take five minutes to eat and have 25 minutes left over, it means you can wander away if you like.
I'm pretty sure labour law supports this definition as well.