Which term is used to define hair that has undergone a loss of color through environmental exposure?

The term used to define hair that has lost color due to environmental exposure is "fade." This phenomenon occurs when hair is subjected to elements such as sunlight, pollution, and harsh weather conditions, which can strip the hair of its pigmentation over time. Fading can also be intensified by chemical treatments or the use of improper hair care products. Understanding fade is essential for haircolorists, as it informs how they select products and techniques to maintain color vibrancy and protect the integrity of the hair.

The other terms do not pertain to the loss of color from environmental exposure. Moisture content refers to the amount of water present in the hair, which influences its health and appearance. Elasticity pertains to the hair's ability to stretch and return to its original shape, indicating hair health but not color loss. Direct dye refers to a type of hair color that deposits pigments onto the hair without needing a developer, but it does not address the effects of environmental factors on color.