alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid 
: any of numerous usually colorless, complex, and bitter organic bases (such as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
Examples of alkaloid in a Sentence
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Nightshades, also known as Solanaceae, produce bitter compounds called alkaloids, which help fend off hungry bugs, animals and fungi.
—
Sarah Kuta, Smithsonian Magazine, 9 July 2025
Researchers suspect the environment may be responsible for the plants’ unexpected return to ancestral alkaloids.
—Sarah Kuta, Smithsonian Magazine, 9 July 2025
Researchers believe the older alkaloids may offer better defense under these tougher conditions.
—Daniella Gray, MSNBC Newsweek, 25 June 2025
Too many alkaloids, though, can make the plant toxic to humans.
—New Atlas, 29 June 2025
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Sarah Kuta, Smithsonian Magazine, 9 July 2025
Researchers suspect the environment may be responsible for the plants’ unexpected return to ancestral alkaloids.
—Sarah Kuta, Smithsonian Magazine, 9 July 2025
Researchers believe the older alkaloids may offer better defense under these tougher conditions.
—Daniella Gray, MSNBC Newsweek, 25 June 2025
Too many alkaloids, though, can make the plant toxic to humans.
—New Atlas, 29 June 2025
See All Example Sentences for alkaloid
Cite this Entry
“Alkaloid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alkaloid. Accessed 20 Aug. 2025.
Copy CitationMedical Definition
alkaloid
noun
al·ka·loid
ˈal-kə-ˌlȯid
: any of numerous usually colorless, complex, and bitter organic bases (as morphine or caffeine) containing nitrogen and usually oxygen that occur especially in seed plants and are typically physiologically active
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