The term for the circle around the Earth at 0 degrees latitude is "the Equator." It divides the Earth into the Northern and Southern Hemispheres and is equidistant from the North and South Poles. The Equator serves as a reference point for measuring latitude, with locations north of it designated as northern latitude and those south as southern latitude. It has significant climatic implications, as areas near the Equator experience a tropical climate with warm temperatures year-round and minimal seasonal variation.