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

Both arise from Schwann cells, the sheathing around nerves, and both hide from the immune system by switching off their MHC molecules. — John Drake, Forbes.com, 27 July 2026

In their new study, the HZDR team says the effect could become especially important for adiabatic quantum computers, a class of machines widely studied for solving optimization problems, searching massive datasets, and simulating molecules. — Rupendra Brahambhatt, Interesting Engineering, 25 July 2026

If a scan shows that cancer cells carry a protein called PSMA, doctors can attach radiation to a molecule that seeks out that protein. — Dr. Jamin Brahmbhatt, CNN Money, 23 July 2026

Microscopically, a fluid is a chaotic jumble of molecules bouncing off one another like billiard balls. — Joseph Howlett, Scientific American, 23 July 2026

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