Same entry in Synagoge sigma119 Cunningham and Photius, Lexicon sigma322 Theodoridis, though there is a discrepancy in transmission over whether the genitive plural headword is skiadi/wn, as printed by Adler, or skiadei/wn (from sigma 594), the reading of mss GVM and of Photius.
The genitive plural occurs in Isaiah 66.20 LXX, in a list of vehicles and animals coming into Jerusalem. (LSJ s.v. translates: 'carriage with a tilt or hood'.) Other attestations are mainly in commentary on this passage.
The gloss is genitive plural of karou/xion, seemingly a diminutive of karou=xa (from Latin carruca "coach").