Other forms: lunchboxes
A lunchbox is the small container a packed midday meal travels in. Sandwiches, an apple, and a note if you are lucky.
It is an object of real significance in childhood, since what is in it and what it looks like are both socially loaded, as any parent knows. Plastic boxes have replaced tins, and reusable ones have replaced cling film. The word is one word. Britain's packed lunch and America's brown bag lunch describe the same thing arriving by different means.
1nounlunchboxA container for carrying a packed meal.
“She found last week's sandwich still in the lunchbox.”
From lunch + box.
Etymology from Wiktionary, CC BY-SA