In this case, I think it's purely that the camera exists on the tripod for the shot. For some, it does mean "locked off"/locked down/static, as Mark pointed out. In my experience, it usually just means that the director just wants a lack of organic human movement in the shot that you would get from handheld, even if the camera doesn't, "move". Tilts/pans/tracking the subject/etc are choices that can be made independent of that sort of thing.