From rakash; a relay of animals on a post-route (as stored up for that purpose); by implication, a courser -- dromedary, mule, swift beast.
see HEBREW rakash
H7409. rekesh
רֶ֫כֶשׁ noun masculineEsther 8:10 collective steeds (connection with √ dubious); — absolute ׳ר Micah 1:13 +, רָ֑כֶשׁ 1 Kings 5:8; — + סוּסִים 5:8, harnessed to chariot Micah 1:13, ridden Esther 8:10 ( + סוּסִים; defined as הָרֵמָּכִים בְּנֵי), 8:14.