The Collaborative International Dictionary of English v.0.48:

Predominate \Pre*dom"i*nate\, v. i. [imp. & p. p.
   Predominated; p. pr. & vb. n. Predominating.] [Pref. pre-
   + dominate: cf. F. pr['e]dominer.]
   To be superior in number, strength, influence, or authority;
   to have controlling power or influence; to prevail; to rule;
   to have the mastery; as, love predominated in her heart.
   [1913 Webster]

         [Certain] rays may predominate over the rest. --Sir. I.
                                                  Newton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Predominate \Pre*dom"i*nate\, v. t.
   To rule over; to overpower. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

predominate
    adj 1: having superior power and influence; "the predominant
           mood among policy-makers is optimism" [syn: overriding,
           paramount, predominant, predominate,
           preponderant, preponderating]
    v 1: be larger in number, quantity, power, status or importance;
         "Money reigns supreme here"; "Hispanics predominate in this
         neighborhood" [syn: predominate, dominate, rule,
         reign, prevail]
    2: appear very large or occupy a commanding position; "The huge
       sculpture predominates over the fountain"; "Large shadows
       loomed on the canyon wall" [syn: loom, tower,
       predominate, hulk]