duo-dē-trīgintā or duo dē xxx adj.
num, twenty-eight: castella, L.
dŭŏ-dē-trīginta, card. num. , twentyeight , Liv. 33, 36 fin. ; Suet. Tib. 1 al. ...
A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.