a circle on the surface of the earth or an other celestial body passing through both poles, or the representation of this on a map or globe

in astronomy, a circle passing through the poles of the celestial sphere (imaginary circle against which stars and planets appear to be placed) and the zenith of a given place

literary a high point, esp of success or greatness

in acupuncture etc, one of the pathways in the body along which vital energy is said to flow