bot'-um: Rendered by several Hebrew words: (1) sheresh, "root"; Chaldaic, shoresh (Job 36:30, "the bottom of the sea"). (2) qarqa', "soil," "pavement of tesserae" (Am 9:3). (3) qetsebh, "cutting," "chop," "extremity" (Jon 2:6, "the bottoms of the mountains"). (4) rephidhah, "railing," "couch" (Song 3:10, "the bottom thereof of gold"). (5) cheq, "bosom," "lap" (Eze 43:13-14,17, the Revised Version, margin "hollow"). (6) metsullah, "to be dark," "shadowy place," from primitive root tsalal, "to tumble down," i.e. "settle"; hence, the idea of a valley ("the myrtle-trees that were in the bottom," Zec 1:8 the Revised Version, margin "shady place"). The prophet may have been wont to frequent the myrtle grove in the glen or bottoms, in the neighborhood of Jerusalem, for meditation and prayer (BTP, II, 283).
⇒See the definition of bottom in the KJV Dictionary
M. O. Evans