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

Until then, businesses in Minnesota and other states where higher THC hemp products are allowed can continue to sell their products. —Esme Murphy, CBS News, 30 Nov. 2025

The authors also noted a dramatic shift in THC potency, with today's products often topping 20% THC, compared to just 5% in the 1990s. —Deirdre Bardolf, FOXNews.com, 29 Nov. 2025

But the funding bill that ended the federal government shutdown earlier this month included a provision cutting the amount of THC — the psychoactive compound responsible for a high — legally allowed in increasingly popular products such as drinks and gummies. —Mary Ramsey, Charlotte Observer, 26 Nov. 2025

Researchers say the rise has unfolded alongside products that contain far more THC than the marijuana of past decades, including vape oils and concentrates that can reach 80% to 95% THC. —Leah Willingham, Fortune, 25 Nov. 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