When you camp, you set up a temporary place to sleep outdoors, often in a tent. Many people like to camp in a beautiful spot, like the mountains or beside a lake.
Use the word camp to describe what you do when you sleep under the stars, and also the site itself — after a day of hiking, you could say, "Let's head back to camp." You can also talk about your usual group of friends or co-workers as your camp. Political parties are described this way sometimes: "She was popular in the Democratic camp." The root is the Latin word campus, which means "open field, or level space."