Same entry, according to Adler, in the Ambrosian Lexicon (298); differently -- highlighting the speed of the horses -- in other lexica. See further below.
This epithet is used principally of the Phrygians: Homer, Iliad 3.185 (= 2.798a), and the Homeric Hymn to Aphrodite 137. (Of Castor in Theocritus, Idylls 22.34; contextless in Cercidas fr. 8.1.) They were famous for their horses, as was, of course, the Trojan plain, where they were a gift of Zeus in payment for Ganymede; cf. E. Delebecque, Le Cheval dans l’Iliade (Paris,1951) esp. 27-30. In the Iliad the ill-fated Asius of Arisbe (Lexikon des frühgriechischen Epos 1.1398-1400) was inordinately proud of his horses and chariot (12.96-173, 13.384-401), as was the Trojan Pandarus (5.192-204). We cannot tell which of their possible characteristics is described by this compound adjective: they were piebald in colour or some other variegation; they were good at turning, i.e. exceptionally nimble in circling the enemy (cf. the native Americans in the Indian Wars); their motion in pulling the chariot was undulant; the undulating motion of their galloping feet was particularly swift; a mass of horses was a mass of different colours. On a Linear B tablet from Cnossos either a stallion or a bull is named a3-wo-ro, probably “Piebald” or “Roan” from his colour (cf. alphaiota 252 note). See alphaiota 253 for these meanings of ai)o/los.