: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The attack happened on Dec. 5, 2022, when Amador used a fake Instagram account to lure Massaro to a remote location, promising a sale of marijuana and THC vapes. Skylar Heisey, The Arizona Republic, 18 Nov. 2024 Secondhand marijuana smoke has many of the same carcinogens and toxic chemicals as secondhand tobacco smoke, along with THC, the active ingredient in cannabis. David Stempel, The Mercury News, 9 Nov. 2024 The 2018 farm bill, for example, legalized hemp, which inadvertently popularized delta-8 THC. Marin Cogan, Vox, 4 Nov. 2024 Nelson’s daily dose of THC is about sixty milligrams—enough to turn a regular person into stardust. Adam Iscoe, The New Yorker, 4 Nov. 2024 See all Example Sentences for THC 

Word History

Etymology

tetrahydrocannabinol

First Known Use

1967, in the meaning defined above

Time Traveler
The first known use of THC was in 1967

Dictionary Entries Near THC

Cite this Entry

“THC.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/THC. Accessed 5 Dec. 2024.

Medical Definition

: 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

More from Merriam-Webster on THC

Last Updated: - Updated example sentences
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