MedicalTerminology DB

Meaning of heroin: A substance made from morphine.

Definition of heroin

A substance made from morphine. Heroin is very addictive and it is illegal to use or sell it in the United States. It is a type of opiate.

Written and maintained by James Murray Last updated July 21, 2026 Educational reference, not medical advice. Read the limitations.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.