tn The passive participle of the verb “to choose” means that these were “choice” or superb chariots.
tn Heb “every chariot of Egypt.” After the mention of the best chariots, the meaning of this description is “all the other chariots.”
tn The word שָׁלִשִׁם (shalishim) means “officers” or some special kind of military personnel. At one time it was taken to mean a “three man chariot,” but the pictures of Egyptian chariots only show two in a chariot. It may mean officers near the king, “men of the third rank” (B. Jacob, Exodus, 394). So the chariots and the crew represented the elite. See the old view by A. E. Cowley that linked it to a Hittite word (“A Hittite Word in Hebrew,” JTS 21 : 326), and the more recent work by P. C. Craigie connecting it to Egyptian “commander” (“An Egyptian Expression in the Song of the Sea: Exodus XV.4,” VT 20 : 85).