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

Intoxicating hemp is made by manipulating compounds found in hemp plants to create toxic compounds like delta-8-THC and delta-9-THC. —Ashley J. Dimella, FOXNews.com, 9 Oct. 2025

State lawmakers have discussed ways to regulate drinks, edibles and other products containing THC derived from hemp but have yet to pass a law. —Enquirer Staff, Cincinnati Enquirer, 8 Oct. 2025

Currently, Wisconsin law limits only delta-9 THC, allowing other intoxicating compounds to slip through the cracks. —Gina Lee Castro, jsonline.com, 3 Oct. 2025

Guests who book a massage have their choice of regular oil or oil infused with THC and CBD, which can help relax the muscles and reduce inflammation. —Tiney Ricciardi, Denver Post, 25 Sep. 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