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

Foundayo is a small-molecule drug, which can be manufactured differently and more easily at scale than peptide drugs such as Novo’s Wegovy pill and existing injectable GLP-1s. — Annika Kim Constantino,elsa Ohlen, CNBC, 25 Sep. 2026

The scientists explained that water molecules adsorbed by the material modify its electronic structure. — Georgina Jedikovska, Interesting Engineering, 25 Sep. 2026

Both of these regions featured different chromatin — a mixture of DNA, RNA, and proteins that packages long DNA molecules — setting them on independent developmental paths. — Victor Tangermann, Futurism, 24 Sep. 2026

So if cells in the head make a different collection of signaling molecules from those in the tail, this can transfer positional information to the developing nervous system, telling it where to form the brain and where to form the spinal cord. — John Timmer, ArsTechnica, 23 Sep. 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