Definition

1. Noun:
   • An imaginary line passing through both magnetic poles of the Earth: A magnetic meridian is a conceptual line on the Earth's surface that connects the North and South Magnetic Poles. It indicates the local direction of the Earth's magnetic field.

Usage

• The term is used in geography, navigation, and geophysics to describe orientation relative to Earth's magnetic field, as opposed to geographic lines.
• It is a fixed conceptual line for a given location, unlike the moving needle of a compass, which aligns with it.
• Example: "To calibrate the compass, it must be aligned with the local ."
• Example: "The angle between the geographic meridian and the at this location is 15 degrees west."

Advanced Usage

• In Navigation: The is the reference line for determining a vessel's or aircraft's magnetic heading. The difference between true north (geographic meridian) and magnetic north () is called magnetic declination.
  • Example: "Pilots must account for the variation between the true meridian and the magnetic meridian when plotting a course."

Variants and Related Words

• Magnetic Declination (Variation) (n): The angle on the horizontal plane between magnetic north (the ) and true north (geographic meridian).
• Magnetic Pole (n): Either of the two points on the Earth's surface where the lines converge and the magnetic field is vertical.
• Geographic Meridian (n): An imaginary line connecting the geographic North and South Poles.

Synonyms

• Magnetic north-south line: A descriptive synonym emphasizing its directional nature.

Related Concepts (Not Phrasal Verbs or Idioms)

• Agonic Line: The line on a map connecting points where the and geographic meridian coincide (i.e., where magnetic declination is zero).
• Isogonic Line: A line on a map connecting points of equal magnetic declination relative to the .

Noun

1. an imaginary line passing through both magnetic poles of the Earth