Final answer:
In Miranda v. Arizona, the Supreme Court defined 'custody' as being detained in a manner similar to a formal arrest, which requires law enforcement to inform the detained individual of their Miranda rights to ensure statements made are voluntary and not self-incriminating.
Step-by-step explanation:
For purposes of the Miranda admissibility rule, "custody" means: Being detained or deprived of freedom to an extent associated with formal arrest. This stems from the landmark case Miranda v. Arizona, where the Court held that prosecutors could not use statements from custodial interrogation unless procedural safeguards were in place.
These safeguards, known as Miranda rights, include the right to remain silent and the right to have counsel present. If a suspect is not advised of these rights, statements made in custody cannot be used against them in court. The Supreme Court decision emphasized the need for law enforcement to respect the privilege against self-incrimination.