NLOS(n.) Short for near line of sight. Radio frequency technologies use the term NLOS to describe a partially obstructed path between the location of the signal transmitter and the location of the signal receiver. Obstacles that can cause an obstruction in the line of sight include trees, buildings, mountains, hills and other natural or manmade structures or objects.
Compare with LOS.
Near line of sight also is less commonly referred to as loose line of sight.