Editorial
Habeas corpushabeas corpus ad subjiciendum
Also: the great writ
Definition
A judicial remedy requiring a person detaining another to produce the detainee before the court and justify the detention. If no lawful basis is shown, the court orders release.
In plain English: A judge orders whoever is holding you to bring you to court and explain why. If they cannot, you go free.
A general definition, not tied to any jurisdiction. Check the meaning in the system that governs your matter before relying on it.