English Reference

Word

proton

Phoneticspro·ton

US/ˈpɹoʊˌtɑn/

UK/pɹˈəʊtɒn/

Definitions

01subatomic particle

B2 · Science

n. a very small piece of matter inside an atom that has a positive electrical charge.

n. a subatomic particle with a positive charge, found in the nucleus of every atom; the number of protons determines the chemical element.

“Hydrogen is the simplest element because its atom has only one proton.”

“The atomic number of an element is defined by the number of protons residing within its nucleus, which remains constant during chemical reactions.”

Technical

Usage

Countable noun; usually discussed in the context of physics or chemistry.

Antonyms

02biology/embryology

C2 · Science

n. an old word for the earliest stage of an organ or tissue in a developing baby or plant.

n. an obsolete synonym for primordium, referring to an organ or part in its most rudimentary form or earliest stage of development.

“In the old textbook, the author used the word proton to describe the start of a leaf.”

“Historical anatomical texts occasionally employ the term proton to denote the primitive cellular structures that eventually differentiate into complex organs.”

Archaic · Technical

Teaching tip

This sense is obsolete; modern students will only encounter 'proton' in a physics context. Use 'primordium' or 'embryo' for biological contexts instead.

Synonyms

primordiumrudiment

Real-World Examples

“Physicists may have uncovered a hidden feature inside protons that helps preserve one of matter’s most fundamental properties.”
ScienceDaily · 16 Aug 2026
“Most of the radiation all these detectors recorded, though, came from the mission’s passage through Earth’s inner Van Allen belt, a region of high-energy trapped protons.”
Ars Technica · 13 Aug 2026
“Though they don’t have mass, the energy involved in binding everything together inside a proton is huge, and a lot of that energy takes the form of mass thanks to E=mc 2 .”
Ars Technica · 12 Aug 2026
“Scientists have identified LHAASO J1912+1014u as a cosmic accelerator that can push protons beyond one quadrillion electron volts.”
ScienceDaily · 2 Aug 2026

Domain

Anatomy

This entry

Level
C1 · Advanced
Frequency
Frequent
Updated

Scan code

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English Reference