Glossary
Pleading
A formal written document that states a party's claims or defenses. Complaints, answers, counterclaims, and replies are all pleadings. Pleadings are different from motions: they frame what the case is about, while motions ask the court to do something.
Pleadings come first: they define the dispute. After the pleadings are settled (everyone has filed and amended them), the case moves into discovery and motion practice. Pleadings are usually limited in number: you typically have a complaint, an answer, and possibly a reply to a counterclaim, and that's it.
Each court has rules about what pleadings have to contain ("pleading standards"). In federal court, the standard from Rule 8 plus the Twombly and Iqbal Supreme Court decisions requires "plausible" factual allegations, not just labels. State court standards vary.