Small, hot rooms where people go to sweat, usually for health or relaxation.
Sweatboxes are usually good because they help people feel better.
Examples:
After exercising, she goes to the sweatbox to relax.
The hotel has a nice sweatbox for guests to use.
He spends 20 minutes in the sweatbox after his workout.
The sweatbox is so hot, it feels like being in an oven.
In some cultures, people use sweatboxes to feel better when they are sick.
The sweatbox is like a small sauna.