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

alkaloidal

ˌal-kə-ˈlȯi-dᵊl 

adjective

Examples of alkaloid in a Sentence

Recent Examples on the Web

History and discovery Buprenorphine is derived from thebaine, an alkaloid that occurs naturally in the opium poppy (Papaver somniferum). — Encyclopedia Britannica, 28 Aug. 2026

Indigenous peoples in the southeast have long utilized a plant called yaupon holly (Ilex vomitoria) for a culturally important drink, which also contains the same alkaloids. — Andrew Paul, Popular Science, 26 Aug. 2026

Unlike its parent alkaloid, 7-OH is a full mu-opioid agonist, estimated to be several times more potent than morphine. — Jesse M. Pines, Forbes.com, 6 Aug. 2026

This plant is toxic, and the seeds contain alkaloid compounds that can be deadly if ingested. — Steve Bender, Southern Living, 21 June 2026

Word History

First Known Use

1820, in the meaning defined above

Rhymes for alkaloid

• adenoid
• amoeboid
• amyloid
• aneroid
• arachnoid
• asteroid
• benzenoid
• carcinoid
• celluloid
• coronoid
• humanoid
• mongoloid

Medical 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

alkaloidal

ˌal-kə-ˈlȯid-ᵊl 

adjective