Constitutional Law Definition:

A branch of law with a focus on constitutions.

The description afforded by the Corpus Juris Secundum is appropriate:

"Constitutional law is that department of law which treats of constitutions and the validity of enactments, as tested by the criterion of conformity to fundamental law.

"It is that branch of the law which treats of the organization and frame of government, the distribution of political and governmental authorities and functions, and fundamental principles which are to regulate the relations of government and citizen, and which prescribe generally the plan and method according to which the public affairs of the nation or state are to be administered.

"A constitutional law is a law which is consonant to and agrees with the constitution; one which is not in violation of the constitution of the particular state."