nuclear

nuclear — adjective

1. relating to the process of creating usable energy by splitting the central part

1.adjectiveB2
Definition

relating to the process of creating usable energy by splitting the central part of an atom (fission) or by joining two atomic centres together (fusion)

Example

Roya's village gets its electricity from a nuclear power station built in 2015.

collocation: nuclear power station

France produces about seventy percent of its electricity from nuclear energy.

collocation: nuclear energy

Common collocations
  • nuclear power
  • nuclear energy
  • nuclear reactor
  • nuclear plant
  • nuclear waste
  • nuclear fission
  • nuclear fusion
  • nuclear fuel
Synonyms
  • atomic

    broader in meaning; 'atomic energy' can refer to any energy from atoms, while 'nuclear energy' specifically refers to reactions in the nucleus

  • thermonuclear

    more specific; refers only to fusion reactions (e.g. a hydrogen bomb or fusion reactor), not general nuclear power

Grammar Patterns

nuclear + noun

Usage Note

This sense is always used before a noun — you cannot say 'The energy is nuclear' to mean it comes from nuclear sources. The noun itself (e.g. power, energy, reactor) carries the specific meaning.

Common Mistakes

The country uses atomic power to generate electricity.' (when meaning nuclear)
The country uses nuclear power to generate electricity.
'Atomic' is broader and less precise; for power generation the standard term is 'nuclear'.
They are building a new nuclear.
They are building a new nuclear reactor / nuclear power plant.
'Nuclear' is an adjective and cannot stand alone as a noun for a facility.

2. relating to bombs, missiles, and other arms that cause enormous explosions by re

2.adjectiveB2
Definition

relating to bombs, missiles, and other arms that cause enormous explosions by releasing energy from the centre of an atom, often with long-lasting radioactive effects

Example

The international treaty aims to stop the spread of nuclear weapons to more countries.

collocation: nuclear weapons

Hui's grandfather worked as a physicist on early nuclear bomb projects during the 1940s.

collocation: nuclear bomb

Common collocations
  • nuclear weapon
  • nuclear bomb
  • nuclear warhead
  • nuclear missile
  • nuclear test
  • nuclear attack
  • nuclear war
  • nuclear arsenal
  • nuclear deterrent
  • nuclear proliferation
  • nuclear disarmament
  • nuclear power (country with nuclear weapons)
Synonyms
  • atomic

    historically used for early nuclear bombs ('atomic bomb'), but 'nuclear' is now the standard term in modern military contexts

  • thermonuclear

    refers specifically to hydrogen bombs that use fusion; a subset of nuclear weapons

Antonyms
  • conventional

    refers to weapons that do not use nuclear reactions (e.g. regular bombs, guns)

Grammar Patterns

nuclear + noun

Usage Note

Frequently paired with nouns describing the weapon itself (bomb, warhead, missile), the act of using it (test, attack, strike), or related policy (deterrent, proliferation, disarmament). Can also describe a country's status: 'a nuclear power' means a country that possesses nuclear weapons, not one that produces nuclear energy.

Common Mistakes

Several countries have nuclear.
Several countries have nuclear weapons.
'Nuclear' cannot function as a noun meaning 'nuclear weapons'.

3. belonging to or having to do with the dense, positively charged centre of an ato

3.adjectiveB2
Definition

belonging to or having to do with the dense, positively charged centre of an atom, which contains protons and neutrons

Example

In science class, Ezra learned that nuclear fission happens when a neutron strikes the centre of a uranium atom.

collocation: nuclear fission

Nuclear physics is the branch of science that studies the behaviour of particles inside the atom's centre.

collocation: nuclear physics

Common collocations
  • nuclear fission
  • nuclear fusion
  • nuclear physics
  • nuclear reaction
  • nuclear decay
  • nuclear mass
  • nuclear force
  • nuclear structure

Grammar Patterns

nuclear + noun

Usage Note

This is the purely scientific sense, distinct from sense 1 (energy production) and sense 2 (weapons). It describes the properties of the atomic nucleus itself — size, structure, behaviour — rather than the practical applications of nuclear reactions. Terms like 'nuclear fission' and 'nuclear fusion' bridge this sense and sense 1; the context determines which meaning is intended.

Common Mistakes

The nuclear of the atom contains protons.
The nucleus of the atom contains protons.
'Nuclear' is an adjective; the noun form is 'nucleus'.

4. forming the most important or essential part around which everything else in a g

4.adjectiveC1
Definition

forming the most important or essential part around which everything else in a group or system is organised

Example

The nuclear family of two parents and their children is still common in many parts of the world.

collocation: nuclear family

Reema's plan contained a nuclear idea from which all the other details followed naturally.

figurative use: nuclear idea

Common collocations
  • nuclear family
  • nuclear idea
  • nuclear question
  • nuclear issue
  • nuclear element
Synonyms
  • core

    more common and natural in modern English; 'core issue' is used far more often than 'nuclear issue'

  • central

    the most neutral and widely understood alternative; works in any context

  • key

    emphasises importance rather than central position; good for arguments, ideas, or roles

Antonyms
  • peripheral

    describes something on the edges of a system, not at its centre

Grammar Patterns

nuclear + noun

Usage Note

This is a figurative, less common use of 'nuclear'. Outside of the fixed phrase 'nuclear family', it is usually clearer to use 'core', 'central', or 'key' instead. Reserve this sense for contexts where the metaphor of a nucleus (something at the centre that holds everything else in place) fits naturally.

Common Mistakes

This is the nuclear question of the project.' (when meaning 'key' or 'central')
This is the core / central question of the project.
'Nuclear' in this sense sounds dated or overly metaphorical; 'core' or 'central' is more natural.

Word family

  • nucleus
    nounB2
  • antinuclear
    adjectiveC1
  • non-nuclear
    adjectiveC1
  • nucleate
    verbC2
  • nucleation
    nounC2

Synonym discussion

Sense: adjective/1

Nuclear is the broadest and most common term, covering all reactions in the atomic nucleus — both fission (splitting) and fusion (joining). Atomic is a wider term that includes all properties of the atom, not just the nucleus; 'atomic energy' is an older, less precise phrase that has largely been replaced by 'nuclear energy' in everyday use. Thermonuclear refers specifically to fusion reactions, especially those used in hydrogen bombs; it is more technical and much narrower. Fissile describes materials (like uranium-235 or plutonium) that can sustain a nuclear fission chain reaction; it is a physics term, not a general alternative for 'nuclear'. In everyday speech, choose nuclear for most contexts; use atomic only when referring to historical events ('the atomic bombings of 1945'), and reserve thermonuclear and fissile for specialist discussions.

nuclear ↗atomic ↗thermonuclearfissile

Common collocations

Nouns

Phrases

  • nuclear power plant
  • nuclear power station
  • nuclear family
  • nuclear weapons programme
  • nuclear non-proliferation treaty

Etymology

LatinEnglish

Derived from the Latin word 'nucleus', meaning 'kernel' or 'inner part' (from 'nux' = nut). The word first entered English in the 1700s as a biological term for the central part of a cell. In the early 1900s, scientists began using it to describe the centre of an atom. After the discovery of nuclear fission in 1938, the modern meanings for energy and weapons emerged rapidly. The figurative sense — describing something as the central or most essential part — grew from the same Latin root but has always been less common than the scientific meanings.