These words function as both nouns and verbs and apply to marks, grooves, ridges or furrows made in a smooth surface. To fold something is to bend it over upon itself so that one part covers another: to fold a blanket; to fold a newspaper; to fold up a road map; Do not fold , spike or mutilate. Used intransitively, the verb fold means to close together with the parts touching or facing: A fan folds . The noun fold may designate a folded or folding part, piece or layer: the folds of the bellows of an accordion. The eyelid is a movable fold of skin that smooths out when lowered over the eye. A double chin is a fatty fold of flesh under the chin. Fold may also apply to a mark made by folding or the hollow between two folded parts: to tear paper evenly along a fold ; He enveloped her in the voluminous folds of his cloak.

A line is a long, straight, slender mark, as one crossing the brow: the lines in her pale, drawn face; a forehead lined by care. The lines in the palm of the hand indicate the flexional folds of the skin which make firm grasping possible. Palmists claim that the so-called life line , head line and heart line are indicative of a person’s fortune. A crease is a mark, ridge or furrow made by folding . Like a line , a crease may indicate the place where something folds ; but a crease is usually considered to be heavier than a line though shallower than a fold . Hence, when the hand is slowly closed, the lines in the palm first deepen into creases , then thicken into folds . Crease is also used of heavy lines about the mouth or eyes or on the forehead: A sullen scowl creased his brow. And it may indicate a line of soreness or tension that results from bending or twisting: The lumpy mattress put a painful crease in his back.

A wrinkle is a small line , crease or fold in a smooth surface, as a furrow made in the forehead by raising the eyebrows. To wrinkle is to contract into alternate ridges and furrows: He wrinkled his brow in concentration. Permanent wrinkles in the skin may result from age, anxiety or excessive exposure to the elements: a wrinkled crone. Applied to fabric, wrinkle indicates a temporary mark made by crushing or rumpling. The verbs wrinkle and crease are synonymous in this sense: Linen wrinkles (or creases ) easily. The noun crease , however, may indicate a deliberate or permanent line, as one of the two sharp edges pressed into men’s trouser legs. In reference to materials, crimp is also rather like wrinkle , but has the sense of deliberate compressing into tiny folds : The dress was beautifully crimped across the bodice. Skin and hair are said to be crimped if in small tight folds or curls. A pleat is a fold of cloth doubled on itself and pressed or sewn in place: a kick pleat ; pleated draperies; a pleated skirt. Pleat may also indicate the way a thing is creased and folded : an accordion pleat .