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 of quantum

Noun

• amount
• quantity

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

While officials highlighted actions taken by the White House to support the quantum industry, there was no sense of partisan performance, the person said. — Rachyl Jones, semafor.com, 8 July 2026

Researchers calculated nine molecular configurations of FLiBe using quantum-centric supercomputing, combining quantum and classical computers to solve a problem that becomes increasingly difficult for conventional computing alone. — Neetika Walter, Interesting Engineering, 8 July 2026

Adjective

The team combined two fast-growing areas of quantum research by using a magnetic topological material to study non-Hermitian physics, an emerging field that examines systems with unconventional behavior. — Aamir Khollam, Interesting Engineering, 10 July 2026

In closed-door discussions with quantum industry leaders at a White House event on Tuesday, government officials pushed the importance of domestic supply chain security, according to a person in attendance. — Rachyl Jones, semafor.com, 8 July 2026

Word History

Etymology

Noun

Latin, neuter of quantus how much

First Known Use

Noun

1567, in the meaning defined at sense 1a

Adjective

1924, in the meaning defined at sense 2

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

Rhymes for quantum

• contemn
• infantum

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