WordNet sense 1 (the collection of rules imposed by authority):

jurisprudence

WordNet sense 2 (the force of policemen and officers):

constabulary, police, police force

WordNet sense 3 (the branch of philosophy concerned with the law and the principles that lead courts to make the decisions they do):

legal philosophy

WordNet sense 4 (a generalization that describes recurring facts or events in nature):

law of nature

WordNet sense 5 (a rule or body of rules of conduct inherent in human nature and essential to or binding upon human society):

natural law

WordNet sense 6 (the learned profession that is mastered by graduate study in a law school and that is responsible for the judicial system):

practice of law