1. not forming an angle; having no angle
Usage: technical; geometry
2. relating to or denoting a line on the Earth's surface along which magnetic declination is zero
Usage: geography; geophysics

Examples

• The agonic line runs through the Earth where true north and magnetic north align.
• Navigators must account for magnetic declination except along the agonic line.
• The curve was described as agonic because it contained no sharp corners or angles.
• In 2020, the agonic line passed through the western United States.
• An agonic surface has no angular features or vertices.