According to McConkie and Millet, in the Book of Mormon we encounter what the world would consider to be an unusual form and meaning for the word zion. In an Old Testament setting, Zion usually has reference to the holy mount or, by extension, to the city of Jerusalem. Here in 1 Nephi 13:37 and in numerous other places (e.g., 2 Nephi 26:29-31; 28:20-21,24; 3 Nephi 16:16-18) Zion seems to represent the gathering place of the believers, the society of the pure in heart, the setting for the Saints.
Thus, once again we find that explanations for the origin and integration of the concepts in the Book of Mormon are not simple tasks, especially for the doubters of the world. [Joseph Fielding McConkie and Robert L. Millet, Doctrinal Commentary on the Book of Mormon, Vol. 1, p. 103]