…a line notionally drawn on the earth equidistant from the poles, dividing the earth into northern and southern hemispheres and constituting the parallel of latitude 0°…
…the projection into space of the earth’s equator; an imaginary circle equidistant from the celestial poles…
…the great circle of the celestial sphere passing as closely as possible through the densest parts of the Milky Way…
…the irregular imaginary line, passing round the earth near the equator, on which a magnetic needle has no dip (see dip4noun4noun4noun)…
…a notional circle on the earth’s surface, the plane of which is equidistant between the north and south magnetic poles and perpendicular to the magnetic field…
