UV stands for ultraviolet. It is a higher energy spectrum than visible light with wavelengths between 100 nm to 400 nm. Based on the International Union of Pure and Applied Chemistry (IUPAC)’s definition (https://goldbook.iupac.org/terms/view/UT07492):
UV-A: 315-400 nm
UV-B: 280-315 nm
UV-C: 200-280 nm
VUV (Vacuum UV): 100-200 nm