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

Multiple painkillers, sleep aids and THC were detected in his system. —Senior Editor, Los Angeles Times, 9 Apr. 2026

Members of Texas’ hemp industry are asking a Travis County Court to halt some of the state’s new rules regulating THC products. —Eleanor Dearman, Fort Worth Star-Telegram, 8 Apr. 2026

Coming out of the pandemic, Jason Dayton, cofounder of Minneapolis Cider Company, got into the hemp THC business after a 2022 state law explicitly legalized the products with certain regulations. —Caroline Cummings, CBS News, 7 Apr. 2026

The measure also bans the sale of nitrous oxide for recreational use, and of cannabinoids derived from hemp plants — including Delta-8, Delta-10, THC-O and THC-P — which are currently unregulated and becoming increasingly potent. —Ilana Arougheti, Kansas City Star, 6 Apr. 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