THC

noun

ˌtē-(ˌ)āch-ˈsē 

: either of two physiologically active isomers C₂₁H₃₀O₂ from hemp plant resin

especially : one that is the chief intoxicant in marijuana

When a person tokes, eats or vapes cannabis, a wave of THC, or tetrahydrocannabinol, washes into the brain.

—Laura Sanders

THC, the main chemical component of marijuana, has been shown to reduce nausea and increase appetite in chemotherapy patients.

—Andrew Weil

THC disappears from blood quickly as it is absorbed in the brain, making blood tests a more reliable measure of recent use but not a great correlate of impairment.

—Eliza Gray

Examples of THC in a Sentence

Recent Examples on the Web

Leaving Molly at home to experiment with blue cheese and THC as brownie ingredients, the Kwik Thingz delivery girl heads out in uniform. — Alison Foreman, IndieWire, 12 Aug. 2026

His legal troubles escalated to jail time in June, after his positive THC test violated a probation specifically designed to stop this conversation from returning for a third installment. — Sam McDowell, Kansas City Star, 12 Aug. 2026

The Wrong Girls A loving ode to the power of friendship and THC. — Angie Han, HollywoodReporter, 12 Aug. 2026

Rice violated his probation after testing positive for THC, which mandated a 30-day jail sentence in Texas. — Scott Thompson, FOXNews.com, 12 Aug. 2026

Word History

Etymology

tetrahydrocannabinol

First Known Use

1967, in the meaning defined above

Medical Definition

THC

noun

ˌtē-ˌāch-ˈsē 

: either of two physiologically active isomers C₂₁H₃₀O₂ that occur naturally in hemp plant resin or are synthetically prepared:

a

: one that is the chief intoxicant in marijuana and is used medicinally

called also delta-9-tetrahydrocannabinol, delta-9-THC

see dronabinol

b

: one that is present in marijuana only in minute quantities