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

Patients can access a wider range of products, including flower, edibles, and inhalable options, with a 12,000mg THC possession limit. — A.j. Herrington, Forbes.com, 27 July 2026

Hagee also said a single THC vape cartridge or a small tin of gummies can often tip the scales into felony territory in Texas, even if the same product was legal where it was purchased. — Tiffani Jackson, Fort Worth Star-Telegram, 24 July 2026

Davidson is accused of attempting to steal 10 THC vape pens from Liles and threatening the use of a firearm, according to court records. — Nadine El-Bawab, ABC News, 23 July 2026

That opened the door for companies to start selling products with THC derived from hemp at retail stores, too. — Sarah Todd, STAT, 21 July 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