gua·​ni·​dine | \ ˈgwä-nə-ˌdēn How to pronounce guanidine (audio) \

Definition of guanidine

: a base CH5N3 derived from guanine that in the form of its hydrochloride acts as a parasympathetic stimulant and is used especially to denature proteins

Examples of guanidine in a Sentence

Recent Examples on the Web Using a main ingredient of sodium hydroxide, lithium hydroxide, potassium hydroxide, or guanidine hydroxide, chemical relaxers break and restructure the bonds in curly hair so that the hair becomes weaker and straight. Ashley Weatherford, The Cut, 15 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'guanidine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of guanidine

circa 1864, in the meaning defined above

History and Etymology for guanidine

International Scientific Vocabulary, from guanine

Learn More About guanidine

Time Traveler for guanidine

Time Traveler

The first known use of guanidine was circa 1864

See more words from the same year

Dictionary Entries Near guanidine




See More Nearby Entries 

Statistics for guanidine

Cite this Entry

“Guanidine.” Dictionary, Merriam-Webster, Accessed 8 Dec. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for guanidine


gua·​ni·​dine | \ ˈgwän-ə-ˌdēn How to pronounce guanidine (audio) \

Medical Definition of guanidine

: a base CH5N3 that is derived from guanine, is found especially in young tissues, and is used in organic synthesis and that in the form of its hydrochloride CH5N3·HCl is used as a drug to enhance acetylcholine activity


Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet pasta spelling help
  • Which is the correct spelling?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!