Glossary
Removal
Moving a case from state court to federal court. Available only when the case could have originally been filed in federal court. Initiated by the defendant filing a notice of removal within strict deadlines.
A defendant sued in state court can sometimes "remove" the case to federal court if the case satisfies federal jurisdiction (federal question or diversity). This is often a tactical choice: defendants may prefer federal court for various reasons (different procedural rules, broader jury pool, perceived sophistication of judges).
Removal has a tight deadline: usually 30 days from when the defendant gets the complaint. If the deadline is missed or the case doesn't qualify for federal jurisdiction, removal isn't available.
The plaintiff can fight back by moving to remand the case to state court, arguing federal jurisdiction doesn't exist.