The Collaborative International Dictionary of English v.0.48:

Rabato \Ra*ba"to\ (r[.a]*b[=a]"t[-o]), n. [F. rabat, fr.
   rabattre. See Rabate.]
   A kind of ruff for the neck; a turned-down collar; a rebato.
   [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rabato
    n 1: a wired or starched collar of intricate lace; worn in 17th
         century [syn: rabato, rebato]