Aqueous/ˈeɪkwiəs/ Definition 1 of 3Pro Tip 1/3Science Context Used often in chemistry and biology to describe water-based environments or solutions. The aqueous solution turned pink after adding the indicator. Pro Tip 2/3Not Always Visible Something aqueous is not necessarily wet to the touch; water might be in a dissolved state. The aqueous mixture inside the battery powers it. Pro Tip 3/3Clear Like Water Aqueous often implies a clear, water-like appearance, but not always colorless. The artist used an aqueous glaze to finish the painting.