Final answer:
Congruence can be defined as 'agreement' which refers to the correspondence or compatibility between two figures in mathematics or opinions and actions more generally.
Step-by-step explanation:
A word that defines congruence is 'agreement' because congruence in mathematics refers to the harmony or correspondence between two figures or objects, such as when two shapes are identical in form and size. In a more general, non-mathematical sense, congruence can mean agreement or compatibility between opinions, actions, or interests.