closed curve(n = noun.shape) - a curve (such as a circle) having no endpoints;
is a kind of curve, curved shape
has particulars: jordan curve, simple closed curve

bell-shaped curve, blind curve, characteristic curve, closed, closed book, closed chain, closed circuit, closed corporation, closed couplet, closed fracture, closed gentian, closed in, closed interval, closed loop, closed minded, closed primary, closed session, closed shop, closed universe, curve, curve ball, exponential curve, frequency-response curve, gaussian curve, jordan curve, laffer curve, normal curve, regression curve, simple closed curve, sine curve