Color is a perception that arises in our visual system when it detects and interprets different wavelengths of light. Each color corresponds to a specific range of wavelengths within the electromagnetic spectrum. So, technically, every color is associated with a wavelength or a range of wavelengths.
However, if you are asking about a color that is not associated with a specific wavelength, white is often considered as a combination of all colors or a blend of different wavelengths across the visible spectrum. In this sense, white light can be seen as having no specific dominant wavelength.
It's worth noting that there are also instances where colors can be perceived without a corresponding single wavelength. For example, certain mixtures of different wavelengths can produce the perception of colors such as magenta, which doesn't have a corresponding single wavelength in the spectrum. Magenta is a non-spectral color and arises from the stimulation of both the red and blue color receptors in our visual system.