The Collaborative International Dictionary of English v.0.48:

Congruous \Con"gru*ous\, a. [L. congruus, fr. congruere to come
   together, to coincide, to agree. Of uncertain origin.]
   Suitable or concordant; accordant; fit; harmonious;
   correspondent; consistent.
   [1913 Webster]

         Not congruous to the nature of epic poetry. --Blair.
   [1913 Webster]

         It is no ways congruous that God should be always
         frightening men into an acknowledgment of the truth.
                                                  --Atterbury.
   [1913 Webster]

WordNet (r) 3.0 (2006):

congruous
    adj 1: corresponding in character or kind [syn: congruous,
           congruent] [ant: incongruous]
    2: suitable or appropriate together