Sky wave refers to the propagation of radio waves that travel long distances by reflecting off the ionosphere layer. Synonyms for sky wave include ionospheric wave, skip wave, and vertical incidence wave. These terms are commonly used in the field of radio communication and can describe the way in which radio signals travel through the atmosphere to reach their intended destination. In contrast to ground waves, which travel close to the surface of the earth, sky waves can travel much further and can be useful in long-range communication. Understanding the various synonyms for sky wave can help improve communication and ensure that messages are received clearly and accurately.