atomic theory

noun

Definition of atomic theory

1 : a theory of the nature of matter: all material substances are composed of minute particles or atoms of a comparatively small number of kinds and all the atoms of the same kind are uniform in size, weight, and other properties
2 : any of several theories of the structure of the atom especially : one based on experimentation and theoretical considerations holding that the atom is composed essentially of a small positively charged comparatively heavy nucleus surrounded by a comparatively large arrangement of electrons

Examples of atomic theory in a Sentence

Recent Examples on the Web But Rovelli says that the degree of confirmation of atomic theory shouldn’t even be measured in the same units as that of string theory. Quanta Magazine, 16 Dec. 2015 String theory is not, say, 10 percent as confirmed as atomic theory; the two have different statuses entirely. Quanta Magazine, 16 Dec. 2015

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

First Known Use of atomic theory

1738, in the meaning defined at sense 1

Learn More About atomic theory

Time Traveler for atomic theory

Time Traveler

The first known use of atomic theory was in 1738

See more words from the same year

Dictionary Entries Near atomic theory

atomic spectrum

atomic theory

atomic volume

See More Nearby Entries 

Statistics for atomic theory

Cite this Entry

“Atomic theory.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/atomic%20theory. Accessed 21 Jan. 2022.

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

More Definitions for atomic theory

atomic theory

noun

Medical Definition of atomic theory

1 : a theory of the nature of matter: all material substances are composed of minute particles or atoms of a comparatively small number of kinds and all the atoms of the same kind are uniform in size, weight, and other properties

called also atomic hypothesis

2 : any of several theories of the structure of the atom especially : one based on experimentation and theoretical considerations holding that the atom is composed essentially of a small positively charged comparatively heavy nucleus surrounded by a comparatively large arrangement of electrons

More from Merriam-Webster on atomic theory

Britannica.com: Encyclopedia article about atomic theory

WORD OF THE DAY

Test Your Vocabulary

Name that Thing: Flower Edition

Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

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