polar circle

English Thesaurus

1. a line of latitude at the north or south poles (noun.location)

hypernym	:	latitude, line of latitude, parallel, parallel of latitude,
definition	:	an imaginary line around the Earth parallel to the equator (noun.location)

instance hyponym	:	antarctic circle,
definition	:	a line of latitude north of the south pole (noun.location)

instance hyponym	:	arctic circle,
definition	:	a line of latitude near but to the south of the north pole; it marks the northernmost point at which the sun is visible on the northern winter solstice and the southernmost point at which the midnight sun can be seen on the northern summer solstice (noun.location)