sinus node


Definition of sinus node

: a small mass of tissue that is embedded in the musculature of the right atrium of higher vertebrates and that originates the impulses stimulating the heartbeat

Examples of sinus node in a Sentence

Recent Examples on the Web Hearts beat when the sinus node, a small mass of tissue in the right upper chamber, transmits an impulse to the heart cells. Michael Ciaglo, National Geographic, 5 June 2020 Over the course of a day, a person’s heart beats about 100,000 times, and each beat begins with an electrical signal generated in the sinus node in the heart’s upper right chamber. Emily Sohn, Washington Post, 7 Mar. 2018

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

First Known Use of sinus node

1937, in the meaning defined above

Learn More About sinus node

Time Traveler for sinus node

Time Traveler

The first known use of sinus node was in 1937

See more words from the same year

Dictionary Entries Near sinus node


sinus node


See More Nearby Entries 

Statistics for sinus node

Cite this Entry

“Sinus node.” Dictionary, Merriam-Webster, Accessed 29 Nov. 2021.

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

More Definitions for sinus node

sinus node


Medical Definition of sinus node


Test Your Vocabulary

Name that Thing: Flower Edition

True or False

Test your knowledge - and maybe learn something along the way.

Love words? Need even more definitions?

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