The Collaborative International Dictionary of English v.0.48:

Germanism \Ger"man*ism\, n. [Cf. F. germanisme.]
   1. An idiom of the German language.
      [1913 Webster]

   2. A characteristic of the Germans; a characteristic German
      mode, doctrine, etc.; rationalism. --J. W. Alexander.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Germanism
    n 1: a custom that is peculiar to Germany or its citizens