VLF stands for very low frequency, which refers to radio frequencies that range from 3 kHz to 30 kHz. Some synonyms for VLF could include low-frequency radio waves or sub-audio frequencies. Another term that could be used is ELF, which stands for extremely low frequency and refers to frequencies below 3 kHz. Other potential synonyms include longwave radio or decameter waves. VLF waves are used for a variety of purposes, including submarine communication, navigation, and scientific research of the ionosphere. With the increasing use of technology, understanding VLF and its synonyms becomes more important in modern communication and research fields.