Satisfying a congruence relation.
Harmonious.
Having a difference divisible by a modulus.
Coinciding exactly when superimposed.
Corresponding in character; congruous
Relating to relations.
Friendly and peaceful.
Dealing with the whole of human relations and their social context, rather than an independent and private space.
Of a database technology using tables and the principles set forth by Dr. Edgar F. Codd. (Contrary to popular notion, "relation" in this context refers to tables, and not linkages.)