any of a number of heterocyclic, colorless, crystalline, bitter organic substances, such as caffeine, morphine, quinine, and strychnine, having alkaline properties and containing nitrogen: they are found in plants and, sometimes, animals, and are used as drugs and stimulants, but can have a strong toxic effect on the human or animal system
Origin of alkaloidalkal(i) + -oid
Any of various organic compounds normally with basic chemical properties and usually containing at least one nitrogen atom in a heterocyclic ring, occurring chiefly in many vascular plants and some fungi. Many alkaloids, such as nicotine, quinine, cocaine, and morphine, are known for their poisonous or medicinal attributes.
Origin of alkaloidalkal(i) + –oid.
(comparative more alkaloid, superlative most alkaloid)
- Relating to, resembling, or containing alkali.
alkali + -oid. Compare French alcaloïde.