From uwr in the sense of raising (i.e. Bearing a burden); properly, a young ass (as just broken to a load); hence an ass-colt -- (ass) colt, foal, young ass.
see HEBREW uwr
H5895. ayir
עַ֫יִר noun masculineGenesis 32:16 male ass (young and vigorous); — plural וַעְיָרִם 32:16 (E); suffix עִירֹה 49:11 (poem; "" אֲתֹנוֺ בְּנִי); construct מֶּרֶא עַיִר (Ges§ 131c N. 2; or appositive KöSynt. § 333 s Di and others) Job 11:12 wild ass's colt; plural עֲיָרִים, for riding Judges 10:4a (10:4b see עִיר), עֲיָרִם), 12:14, singular absolute עַיִר Zechariah 9:9; עֲיָרִים for carrying Isaiah 30:6 Qr (Kt עורים), עֲיָרִם for tillage 30:24.