From rakab; a vehicle; by implication, a team; by extension, cavalry; by analogy a rider, i.e. The upper millstone -- chariot, (upper) millstone, multitude (from the margin), wagon.
see HEBREW rakab
H7393. rekeb
רֶ֫כֶב noun masculine2 Kings 13:7 [even Nahum 2:5, where read מַרְאֵיהֶם (for הֶן-) We Now AlbrZAW xvi (1896), 90] chariotry, chariot, mill-stone; apparently also riders (compare LagBN 151); — absolute ׳ר Genesis 50:9 +, רָ֑כֶב 2 Samuel 8:4 +; construct דֶכֶב Exodus 14:9 +; suffix דִכְבִּי Judges 4:7 +, רִכְבּוֺ 2 Kings 5:9 +, דִכְבָּהּ Nahum 2:14; plural construct רִכְבֵי Song of Solomon 1:9; — Hosea 10:13 see below; —
1109 collective chariotry, chariots [sometimes of specific no. 2 Kings 13:7; 2 Samuel 8:4; Exodus 14:7 etc.; often + מָּרָשִׁים, (ים) סוּס], especially war-chariots : in Egypt 14:7 (J), Joshua 24:6 (E) +; early Canaan 11:4; Judges 4:7, 13; 5:28 (not singular; "" מַרְכְּבוֺתָיו) +, called ׳ר כַּרְוֶל (i.e. iron-bound, or studded, compare GFM1:2 19and references), Joshua 17:16, 18; Judges 1:19; 4:3, 13 ; Philistine, according to 1 Samuel 13:5; 2 Samuel 1:6; Aram 8:4; 10:18 +; Judah and Israel (from David's time, compare 8:4) 1 Kings 9:19, 22; 10:26 +, read also בְּרִכְבְּךָ Hosea 10:13 (for בְּדַרְכְּךָ) ᵐ5B We Now GASm; Assyria 2 Kings 19:23 = Isaiah 37:24; Nahum 2:4; 2:5; Nahum 2:14 (to be burnt; made mainly of wood); Babylon Jeremiah 47:3 (on title 47:1, see Gf Gie), 50:37; 51:21; Ezekiel 23:24 +, etc.; for dignity and display 1 Kings 1:5; 2 Kings 5:9; Jeremiah 17:25; 22:4; Isaiah 66:20, compare Genesis 50:9 (J), (compare also 1 Kings 9:19, 22; 10:26, etc.); figurative of Elijah, ׳ר וּפָרָשׁיו יִשְׂרָאֵל 2 Kings 2:12, of elisha 13:14; אֵשׁ רֶכֶב 2:11 chariotry of fire (at Elijah's translation); ׳ר אֵל Psalm 68:18 chariots of El, i.e. his heavenly host, compare vision 2 Kings 6:17, and also 7:6; ׳ר meton, for chariot-horses 2 Samuel 8:4 = 1 Chronicles 18:4.
2 of single chariot 1 Kings 22:35, 38; 2 Kings 9:21 (twice in verse); 9:24; 10:16; 2 Chronicles 35:24, probably also Exodus 14:6; plural פַרְעֹה רִכְבֵי Song of Solomon 1:9.
3 upper millstone (as riding on the lower) Deuteronomy 24:6; Judges 9:53; 2 Samuel 11:21.
4 apparently = riders (collective), troop (of riders): סוּסִים רֶכֶב שְׁנֵי 2 Kings 7:14 **read perhaps רֹכְבֵי, compare ᵐ5 and 9:16 Bur.; two riders of horses, horsemen (ro two chariots drawn by horses ?); in following text dubious: ׳ד ר פָרָשִׁים ׳צֶמֶד ר ׳חֲמוֺר גָּמֶל Isaiah 21:7 riders, namely a pair of horsemen, ass-riders, camel-rides; compare ׳ר מָּרָשִׁים צֶמֶד אִישׁ 21:9 i.e. men riding, a pair of horsemen; ׳בְּד מָּרָשִׁים אָדָם 22:6 with riders (consisting of) men, horsemen, but use of אָדָם very improbable; attractive is with chariotry of (drawn by) steeds (׳א as gloss) Du CheHpt Di-Kit but ׳פ hardly steeds here (compare ׳פ horsemen, 22:7); read perhaps simply ׳בְּר ׳וּפ.