The drug diacetylmorphine, originally developed as a narcotic analgesic, now seldom used in medicine because of its highly addictive nature, but…

slang (originally U.S.). Any of various intoxicating or narcotic drugs, esp. heroin; such drugs collectively. Cf. junkie, n. 2a.

Heroin or a similar narcotic (see quots.). slang (originally U.S.).

Any of several narcotic or intoxicating drugs, esp. heroin. Cf. smack, n.4

A drug, spec. heroin.

Heroin. slang (originally U.S.).

slang (chiefly British). Drugs, narcotics; (also) a particular drug, esp. marijuana or heroin.

U.S. slang. Heroin. Also with the, that. Cf. girl, n. 10.

transferred and figurative uses, phrases, etc. slang (originally U.S.). A narcotic drug: spec. (a) heroin; brown sugar (see quot. 1974); (b) LSD…

Chiefly in Spanish-speaking contexts: heroin.

Heroin.

= horse, n. 15. U.S. slang.

slang. Heroin. Cf. shit, n. 5.

U.S. slang. A type of high-purity heroin. Cf. P, n. 10k.

an exceptionally pure form of heroin originating in Mexico.