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Meaning of great circle

great' cir'cle

Pronunciation: [key]
  1. a circle on a spherical surface such that the plane containing the circle passes through the center of the sphere. Cf. small circle.
  2. a circle of which a segment represents the shortest distance between two points on the surface of the earth.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.