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

Sales can resume after a judge paused the Ohio governor's ban on THC gummies and beverages. —Katie Wiseman, IndyStar, 14 Oct. 2025

Here's what to know about the Ohio ban and what the THC laws are in Kentucky. —Marina Johnson, Louisville Courier Journal, 14 Oct. 2025

Multiple students at Princeton Middle School were hospitalized last week after eating THC gummies on school grounds, according to Sharonville police. —Brenda Ordonez, Cincinnati Enquirer, 14 Oct. 2025

The store also sells packaged drinks that combine THC and caffeine, which allows users to experience a high without the sleepy effect. —Sara Hansen, Denver Post, 13 Oct. 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