The Collaborative International Dictionary of English v.0.48:

Dragoman \Drag"o*man\, n.; pl. Dragomans. [From F. dragoman,
   or Sp. dragoman, or It. dragomanno; all fr. LGr. ?, Ar.
   tarjum[=a]n, from the same source as E. targum. Cf.
   Drogman, Truchman.]
   An interpreter; -- so called in the Levant and other parts of
   the East.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dragoman
    n 1: an interpreter and guide in the Near East; in the Ottoman
         Empire in the 18th and 19th centuries a translator of
         European languages for the Turkish and Arab authorities and
         most dragomans were Greek (many reached high positions in
         the government)

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DRAGOMAN. An interpreter employed in the east, and particularly at the
Turkish court.
     2. The Act of Congress of August 26, 1842, c. 201, s. 8, declares that
it shall not be lawful for the president of the United States to allow a
dragoman at Constantinople, a salary of more than two thousand five hundred
dollars.