"diffused and perceptible wetness," mid-14c., from Old French moistour "moisture, dampness, wetness" (13c., Modern French moiteur), from moiste (see moist).
Entries linking to moisture
moist adj.
late 14c., "slightly wet; well-irrigated, characterized by moistness," from Old French moiste "damp, wet, soaked" (13c., Modern French moite), which is of uncertain origin. Perhaps from Vulgar Latin *muscidus "moldy," also "wet," from Latin mucidus "slimy, moldy, musty," from mucus "slime" (see mucus). Alternative etymology [Diez] is from Latin musteus "fresh, green, new," literally "like new wine," from musteum "new wine" (see must (n.1)). If this wasn't the source, it influenced the form of the other word in Old French. Related: Moistly; moistness (mid-14c.).
moisturize v.
"impart moisture to, remove dryness, make slightly damp or wet," 1915 (implied in moisturizing), in reference to a commercial egg incubator, from moisture + -ize. By 1953 in reference to creams and lotions for the skin. Related: Moisturized; moisturization.