molecule

noun

mol·​e·​cule ˈmä-li-ˌkyül 

1

: the smallest particle of a substance that retains all the properties (see property sense 1a) of the substance and is composed of one or more atoms (see atom sense 1a)

a molecule of water

a molecule of oxygen

2

: a tiny bit : particle

There is a molecule of evidence to support these charges.

Synonyms of molecule

• particle
• speck
• atom
• bit
• patch
• fleck
• grain
• snippet
• scrap
• granule
• mouthful
• crumb
• shred

Examples of molecule in a Sentence

There is not a molecule of evidence to support these charges.

not a molecule of sense in that girl

Recent Examples on the Web

Identifying potential biosignatures The key idea behind our framework is that life produces molecules with purpose, while nonliving chemistry does not. —Amirali Aghazadeh, The Conversation, 12 Dec. 2025

The team found that molecules such as silicon monoxide, water vapor, and aluminum monoxide appear exactly where clumpy dust clouds were seen in the VLT data. —Robert Lea, Space.com, 11 Dec. 2025

Hydrolysis is a process that breaks down the large collagen molecule into its smaller peptides, which are then processed into products sold as collagen peptides. —Sara Hoffman, Verywell Health, 9 Dec. 2025

Use of natural molecules For solid-state batteries based on organic materials, achieving high capacity and reliability in cold weather is a remarkable and uncommon feat. —Mrigakshi Dixit, Interesting Engineering, 9 Dec. 2025

Word History

Etymology

French molécule, from New Latin molecula, diminutive of Latin moles mass

First Known Use

1701, in the meaning defined at sense 1

Rhymes for molecule

• minuscule
• overrule
• poiseuille
• reticule
• ridicule
• vestibule
• ampoule
• bascule
• carpool
• cesspool
• ferrule
• footstool

Kids Definition

molecule

noun

mol·​e·​cule ˈmäl-i-ˌkyü(ə)l 

1

: the smallest particle of a substance having all the characteristics of the substance

a molecule of water

a molecule of oxygen

2

: a very small bit : particle

Medical Definition

molecule

noun

mol·​e·​cule ˈmäl-i-ˌkyü(ə)l 

: the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms