The Collaborative International Dictionary of English v.0.48:

Flamen \Fla"men\, n.; pl. E. Flammens, L. Flamines. [L.]
   (Rom. Antiq.)
   A priest devoted to the service of a particular god, from
   whom he received a distinguishing epithet. The most honored
   were those of Jupiter, Mars, and Quirinus, called
   respectively Flamen Dialis, Flamen Martialis, and Flamen
   Quirinalis.
   [1913 Webster]

         Affrights the flamens at their service quaint.
                                                  --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

flamen
    n 1: a priest who served a particular deity in ancient Rome