Definitions for "NLOS"
Non Line of Sight. No line can be drawn between two transmitting devices. Total visual blockage has occurred between the transmitting and receiving devices. Extremely large amounts of reflection, refraction and diffraction can occur on a direct ray between the transmitter and receiver.
Nonline of Sight
Non Line-of-Sight. Refers to a condition in wireless communication where a signal arrives at the receiver through reflections, scattering, and diffractions. Also see LOS.
RF engineers use the term NLOS to describe a partially obstructed path between the location of the signal transmitter and the location of the signal receiver.