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

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

Daffodils contain lycorine and other alkaloids that are toxic to most mammals, including squirrels, Hardt explains. — Madeline Buiano, Martha Stewart, 20 Apr. 2026

This is the name for a polypeptide alkaloid that is a derivative of ergot and mimics the activity of dopamine according to CNN. — Gabrielle Rockson, PEOPLE, 29 May 2026

That same alkaloid is also in kratom products as a result of the drying phase of the manufacturing process, Grundmann said — typically 1% to 2% or less of the total content of leaf kratom products and some extracts. — Kristen Rogers, CNN Money, 27 Mar. 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