: 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 A number of new rules could soon go into effect in Washington County parks, including a ban on marijuana and THC products. Mary Divine, Twin Cities, 24 Apr. 2024 Its effects are weaker than delta-9 THC, the intoxicating component found in marijuana. John Tufts, The Indianapolis Star, 20 Apr. 2024 Various people interviewed for this article said that 3- to 5-milligram products were good for beginners, and more experienced THC consumers could start with products that have 10 milligrams of THC. Jordyn Noennig, Journal Sentinel, 19 Apr. 2024 The mother further told police that a caseworker visited the home because her newborn had tested positive for THC, the chief intoxicant in marijuana. Sarah Nelson, The Indianapolis Star, 15 Apr. 2024 That month, at a court hearing, Anderson’s probation agent reported Anderson was testing positive for cocaine, THC and alcohol. Elliot Hughes, Journal Sentinel, 11 Apr. 2024 Jocelyn Stewart, Rosario’s attorney, told NBC San Diego that the corps said the action violated a corps restriction placed on him for allegedly testing positive for THC, the psychoactive ingredient in marijuana. Bill Feather, NBC News, 11 Apr. 2024 Last year, Davis-Woodhall was stripped of her national indoor title and given a one-month suspension after testing positive for THC, a chemical found in cannabis, marijuana and hashish. George Ramsay, CNN, 9 Apr. 2024 Studies have shown that THC, one of the main cannabinoids found in cannabis, can significantly reduce rates of anxiety and traumatic memories related to trauma and PTSD by reducing activity in the amygdala and reduces cognitive distractions by inhibiting activity in the prefrontal cortex. Sarah Sinclair, Forbes, 29 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'THC.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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 3 May. 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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