The Collaborative International Dictionary of English v.0.48:

Merovingian \Mer`o*vin"gi*an\, a. [From Merovaeus, the Latin
   name of a king of the Franks.]
   Of or pertaining to the first Frankish dynasty in Gaul or
   France. -- n. One of the kings of this dynasty.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Merovingian
    adj 1: of or relating to the Merovingian dynasty or its members
    n 1: a member of the Merovingian dynasty
    2: a Frankish dynasty founded by Clovis I that reigned in Gaul
       and Germany from about 500 to 750 [syn: Merovingian,
       Merovingian dynasty]