means the close monitoring of a person, group, or place, often secretly, to gather information or maintain control

from Straight from the French surveillance, 'a watching over,' built from sur- ('over,' from Latin super) plus veiller ('to watch,' from Latin vigilare, 'to be awake or watchful' — the same vigilant root that keeps a vigil burning). The word entered English in the early 19th century, riding in on the paranoia of post-Revolutionary France, where committees kept anxious watch over suspected enemies of the state.