资料来源 : Webster's Revised Unabridged Dictionary (1913)

Ultra- \Ul"tra-\, a.
   A prefix from the Latin ultra beyond (see {Ulterior}), having
   in composition the signification beyond, on the other side,
   chiefly when joined with words expressing relations of place;
   as, ultramarine, ultramontane, ultramundane, ultratropical,
   etc. In other relations it has the sense of excessively,
   exceedingly, beyond what is common, natural, right, or
   proper; as, ultraconservative; ultrademocratic,
   ultradespotic, ultraliberal, ultraradical, etc.