Source : Webster's Revised Unabridged Dictionary (1913)

Preconception \Pre`con*cep"tion\, n.
   The act of preconceiving; conception or opinion previously
   formed.

Source : WordNet®

preconception
     n 1: an opinion formed beforehand without adequate evidence; "he
          did not even try to confirm his preconceptions" [syn: {prepossession},
           {parti pris}, {preconceived opinion}, {preconceived
          idea}, {preconceived notion}]
     2: a partiality that prevents objective consideration of an
        issue or situation [syn: {bias}, {prejudice}]