Zion means, literally, a "sunny place" or "sunny mountain." It first designated an eminence in Palestine on which Jerusalem is built. In the Doctrine and Covenants, Zion has three designations: First, the land of America; second, a specific place of gathering; and third, the pure in heart.
-- David O McKay; “Zion Shall Flourish,” Improvement Era, February 1959, 33.