quantum

1 of 2

noun

quan·​tum ˈkwän-təm 

plural quanta ˈkwän-tə 

1

a

: quantity, amount

b

: portion, part

c

: gross quantity : bulk

2

a

: any of the very small increments or parcels into which many forms of energy are subdivided

b

: any of the small subdivisions of a quantized physical magnitude (such as magnetic moment)

quantum

2 of 2

adjective

1

: large, significant

a quantum improvement

2

: of, relating to, or employing the principles of quantum mechanics

quantum physics

Synonyms

Noun

• amount
• measure
• quantity
• volume

Examples of quantum in a Sentence

Noun

the sum of human knowledge is now so immense that even a highly educated person can hope to absorb only a tiny quantum of it

Recent Examples on the Web

Noun

The agencies provide the financial backbone for American efforts to treat cancer, address rising sea levels, advance quantum computing and much more. —Raymond Zhong, New York Times, 16 Feb. 2025

Where is Google and the overall quantum computing field now? —Matt Grobar, Deadline, 11 Feb. 2025

Adjective

In addition, our Quantum Startup Foundry has collaborated with nearly 50 quantum startups in the past three years, providing the physical and virtual resources necessary to support entrepreneurs and businesses in their quest to get quantum technology to market. —Darryll J. Pines, Baltimore Sun, 9 Feb. 2025

In contrast, digital quantum computers run sequences of elementary operations called quantum logic gates on a set of qubits. —IEEE Spectrum, 6 Feb. 2025

Word History

Etymology

Noun

Latin, neuter of quantus how much

First Known Use

Noun

1567, in the meaning defined at sense 1a

Adjective

1942, in the meaning defined at sense 1

Phrases Containing quantum

• light quantum
• magnetic quantum number
• quantum chromodynamics
• quantum computer
• quantum dot
• quantum electrodynamics
• quantum entanglement
• quantum field theory
• quantum jump
• quantum leap
• quantum mechanics
• quantum number
• quantum theory

Kids Definition

quantum

1 of 2 noun

quan·​tum ˈkwänt-əm 

plural quanta ˈkwänt-ə 

: the smallest amount of many forms of energy (as light)

quantum

2 of 2 adjective

: of or relating to the principles of quantum theory

quantum physics

Medical Definition

quantum

noun

quan·​tum ˈkwänt-əm 

plural quanta ˈkwänt-ə 

1

: one of the very small increments or parcels into which many forms of energy are subdivided

a molecule of rhodopsin in the human eye can cause a response to a single quantum of light

2

: one of the small molecular packets of a neurotransmitter (as acetylcholine) released into the synaptic cleft in the transmission of a nerve impulse across a synapse