Legal practice is sometimes used to distinguish the body of judicial or administrative precedents, rules, policies, customs, and doctrines from legislative enactments such as statutes and constitutions which might be called "laws" in the strict sense of being commands to the general public, rather than only to a set of parties.
[1] In the legal practice that emerged in royal courts under Henry II any case had to fit into a narrowly defined form of pleading usually called a "writ".
The non-conflicting parts of the English and American common law and its forms of pleading were explicitly incorporated into the U.S. Constitution.
Before the Federal Rules of Civil Procedure (FRCP) were enacted in 1938, common law pleading was more formal, traditional, and particular in its phrases and requirements.
Notice pleading, by contrast, simply requires a "short and plain statement" showing only that the pleader is entitled to relief.
There has been some controversy over whether the FCRP violate the Eighth Amendment requirement of common law rules, but the usual answer has been that the changes are only in form and not in substance.