1. (noun) a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center

• celestial equator
• equinoctial
• equinoctial circle
• equinoctial line
• celestial horizon
• horizon
• ecliptic
• equator
• hour circle
• line of longitude
• meridian
• vertical circle

1. (noun) a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center

• line