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

The bill, introduced by the Justice and Development Party (AK Party), led by President Recep Tayyip Erdoğan, published in the Official Gazette yesterday, regulates access to medical cannabis products that are non-intoxicating and low in THC, such as those containing CBD. —Dario Sabaghi, Forbes.com, 25 July 2025

Past research, Jansen notes, has found that cannabis can suppress the immune system through its active compounds: CBD, THC and other minor cannabinoids. —Hannah Millington, MSNBC Newsweek, 25 July 2025

More than 10 grams of cocaine in individual packages, along with numerous items of THC, were seized. —Chris Ramirez, jsonline.com, 25 July 2025

Other items on the agenda for the special legislative session include a congressional redistricting plan, which could create more seats for Republicans, and a second attempt at regulating THC, the psychoactive compound found marijuana. —Julia Jacobo, ABC News, 23 July 2025

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