The part of the electromagnetic spectrum that humans can see is called the visible spectrum or visible light. It consists of electromagnetic radiation with wavelengths approximately between 380 and 750 nanometers (nm). This range corresponds to frequencies roughly between 400 and 790 terahertz (THz). The visible spectrum includes the colors that form the familiar rainbow sequence: violet, indigo, blue, green, yellow, orange, and red (often remembered as ROYGBIV), with violet having the shortest wavelength near 380 nm and red the longest near 700-750 nm. Though these boundaries are not sharply defined and may differ slightly between individuals, this narrow band of wavelengths is the only part of the spectrum detectable by the human eye. Other parts of the electromagnetic spectrum, such as ultraviolet or infrared, are invisible to humans without specialized instruments. Visible light enables the perception of colors and is critical for human vision.