Define the term "line-of-sight" in communications.

The term "line-of-sight" in communications refers to a direct path between the transmitter and the receiver that is unobstructed by physical objects such as buildings, trees, or terrain. This concept is crucial in wireless communication because it affects signal strength and quality. A clear line of sight allows for more effective transmission of signals, as any obstruction can lead to signal degradation or loss, which impacts overall communication effectiveness. Thus, ensuring a clear line of sight is essential for systems that rely on visual paths, such as microwave links or point-to-point radio systems.