Lewis & Short

2. dextrā, praep. [orig. dextrā, abl. of preceding], on the right of (post-Aug.); with acc.: dextra sinistraque januam, Gell. 16, 5, 3: dextra viam stratam, Liv. 8, 15, 8: dextra ac sinistra aquilonem, Vitr. 1, 6, 10; id. 6, 11, 3; Paul. ex Fest. p. 206, 18 al.