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

Accurate Dosing: Calculating the correct dosage requires knowing the THC content of your cannabis and the amount used in the infusion. —Matt Rozo, The Mercury News, 26 Mar. 2025

Pro Tip: When cooking with infused olive oil, keep the heat low to avoid burning off the THC. —Matt Rozo, The Mercury News, 13 Mar. 2025

Eventually, regulators tested the company’s products and found the presence of a solvent called methylene chloride, which is used in a chemical process to convert cannabidiol (CBD) from hemp into THC. —Tiney Ricciardi, The Denver Post, 13 Mar. 2025

Zoom in: As of now, the state has no limits on cannabinoids with psychoactive effects much like those of THC, such as delta-8 — which is often seen in products on shelves across the Triangle — THC-O, HHC, THC-A, delta-7 and delta-10. —Lucille Sherman, Axios, 12 Mar. 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