During the 20th century the meaning gradually narrowed to a small or mid-sized meal eaten at midday. Lunch is commonly the second meal of the day after breakfast. The meal varies in size depending on the culture, and significant variations exist in different areas of the world.
Since lunch typically falls in the early-middle of the working day, it can either be eaten on a break from work, or as part of the workday.
The difference between those who work through lunch and those who take it off could be a matter of cultural, social class, bargaining power, or the nature of the work. Also, to simplify matters, some cultures refer to meal breaks at work as “lunch” no matter when they occur – even in the middle of the night. This is especially true for jobs that have employees that rotate shifts.