an encampment: a body of people gathered in one place, whether an army in the field or a traveling community at rest
This word names a group of people settled together in a place, and by extension the place itself. Its starting point is the act of pitching tents and stopping for the night, so it pictures a community with all its people, animals, and goods drawn together within a marked boundary. Most often that community is an army, so the word slides easily between the campsite and the fighting force that fills it.
The senses below are not different words but one idea seen in different settings. When the people in view carry weapons, the camp is a war camp and often stands for the army itself. When the people in view are a whole nation on the move, the camp is their living quarters, and the writers care a great deal about what may and may not happen inside its boundary. When the group is simply a band of travelers, the word keeps its plainest sense of a company gathered together.
What holds the senses together is the marked-off space and the gathered people inside it. Whether the threat is an enemy or uncleanness, the camp has an inside and an outside, and crossing that line matters.