Wiktionary
closed curve
n. (context topology English) A map from the circle, ''S''1, to a topological space.(McLarty, p. 4)
WordNet
closed curve
n. a curve (such as a circle) having no endpoints
Usage examples of "closed curve".
She smiled, an odd closed curve of the lips, and scratched expertly behind his ears.
A spaceship that goes up to orbit and comes back down to the same place is following a closed curve.
She smiled with a peculiar closed curve of the lips, her green eyes holding a secret mockery.
A closed curve-the perfume is not the odor of her body, but an artificial simulation of it.
It ran in a closed curve from the base of his skull up through the temples to intersect his eye sockets.
I may be a closed curve, but, closed or open, I neither have a beginning nor an end.