Heroin Definition

hĕrō-ĭn

noun

A white, crystalline powder, an acetyl derivative of morphine, C₁₇H₁₇NO(C₂H₃O₂)₂: it is a very powerful, habit-forming narcotic whose manufacture and import are prohibited in the U.S.

Webster's New World

A powerful and addictive drug derived from opium producing intense euphoria classed as an illegal narcotic in most of the world.

Wiktionary

Synonyms:

Origin of Heroin

Since the 1890s from a German trademark, from Ancient Greek ἥρως (hērōs, “hero”) (due to the feelings of power and exaltation while under the influence of the drug).

From Wiktionary
German originally a trademark

From American Heritage Dictionary of the English Language, 5th Edition