(n): unusual darkening of the skin
(n): a light brown the color of topaz
(n): a brown that is light but unsaturated
(n): ratio of the opposite to the adjacent side of a right-angled triangle
(n): function of an angle expressed as a ratio of the length of the sides of right-angled triangle containing the angle
(v): treat skins and hides with tannic acid so as to convert them into leather
(v): change the nature, purpose, or function of something
(v): get a tan, from wind or sun
(v): change color, often in an undesired manner
(adj): of a light yellowish-brown color
(adj): vs. achromatic) -- (being or having or characterized by hue