Extended Strong's Greek Lexicon (Abbott-Smith based)
donkey
Usage: ὑπο-ζύγιος, -α, -ον [in LXX for חֲמוֹר ;] under the yoke; as subst., τ . (Hdt., al.), a beast of burden; colloq., an ass (see Deiss., BS, 160 f.), and so always in LXX and NT: Mat.21:5 (LXX), 2Pe.2:16.† (AS)