coincidence

coincidence — noun

1. an unexpected situation in which two or more unconnected events occur at the sam

1.nounB2
Definition

an unexpected situation in which two or more unconnected events occur at the same moment, making it seem as though they are related.

Example

By pure coincidence, Aiko and her brother chose the same birthday card for their mother.

collocation: pure coincidence

It was a strange coincidence that the power went out just as Diego began speaking.

coincidence + that-clause

Common collocations
  • pure coincidence
  • sheer coincidence
  • strange coincidence
  • incredible coincidence
  • happy coincidence
  • mere coincidence
Synonyms
  • fluke

    more informal; suggests a lucky accident rather than any connection

  • accident

    broader; refers to anything happening without intention, not necessarily simultaneous

  • happenstance

    formal or literary; emphasises the role of chance

Antonyms
  • intention

    a planned, deliberate outcome rather than a chance event

  • design

    something carefully arranged, not left to chance

Grammar Patterns

coincidence + that-clause

Usage Note

Often used with 'pure', 'sheer', or 'strange' to emphasise the surprising nature of the event. A that-clause frequently follows the noun (e.g., 'It was a coincidence that...').

Common Mistakes

It was an irony that we wore the same shirt.
It was a coincidence that we wore the same shirt.
Coincidence is about unconnected events occurring together; irony is about an outcome that is the opposite of what one expects.

2. the way in which events happen without any plan or deliberate cause, driven simp

2.nounB2
Definition

the way in which events happen without any plan or deliberate cause, driven simply by luck or chance.

Example

Leila met her cousin in Rome entirely by coincidence.

collocation: by coincidence

It is no coincidence that children who read a lot also tend to write well.

pattern: it is no coincidence that…

Common collocations
  • by coincidence
  • through coincidence
  • by pure coincidence
  • it is no coincidence
Synonyms
  • chance

    broader and more neutral; the general idea of unplanned events

  • luck

    adds a positive or negative flavour depending on context

  • fate

    suggests a predetermined outcome, which is the opposite of randomness

Antonyms
  • design

    deliberate planning rather than chance

  • intention

    a conscious purpose behind an event

Grammar Patterns

coincidence + that-clause

Usage Note

Primarily appears in the fixed phrase 'by coincidence' or the expression 'it is no coincidence that + clause'. This sense is uncountable — do not precede it with 'a' or 'an'.

Common Mistakes

They met by a coincidence.
They met by coincidence.
When 'coincidence' means chance or luck, it is uncountable and takes no article.

3. the condition in which several ideas, accounts, or positions match one another e

3.nounC1
Definition

the condition in which several ideas, accounts, or positions match one another exactly, suggesting that they are in agreement.

Example

There is a striking coincidence of opinion among the experts on this question.

collocation: coincidence of opinion

A coincidence of interests led the Huang and Chen families to launch a joint business.

collocation: coincidence of interests

Common collocations
  • coincidence of opinion
  • coincidence of interests
  • coincidence of views
  • coincidence of purpose
  • coincidence of data
Synonyms
  • correspondence

    more neutral; suggests two things matching point by point

  • agreement

    broader; can apply to people or data being in harmony

  • concurrence

    formal; emphasises simultaneous agreement

Antonyms

Grammar Patterns

coincidence of + noun phrase

Usage Note

Formal register; typically used in academic, legal, or analytical writing. The pattern 'coincidence of + noun' (e.g., coincidence of opinion, coincidence of interests) is the most common structure. Avoid using this sense in casual conversation.

Word family

  • coincide
    verbB2
  • coincident
    adjectiveC1
  • coincidental
    adjectiveB2
  • coincidentally
    adverbB2

Synonym discussion

Sense: noun/1

Coincidence (B2) is the most specific of these words: it refers to two or more events happening at the same time by chance, often in a way that feels connected. Chance (B1) is broader — it covers any event without a known cause, including good or bad luck, and does not require simultaneity. Accident (A2) usually describes an event that causes harm or damage unintentionally, though it can also mean something happening by chance ('by accident'). Serendipity (C1) is a more literary term for a lucky accident where something good is discovered by chance. Fate (B2) is the opposite of coincidence in philosophy: fate implies a predetermined plan, whereas coincidence suggests randomness. For example: 'It was a coincidence that we both chose the same restaurant' (unconnected but simultaneous) vs. 'We met by chance' (no plan, but not necessarily at the same time) vs. 'Finding that bookshop was pure serendipity' (a positive, unexpected discovery).

coincidence ↗chance ↗accident ↗serendipity ↗fate ↗

Common collocations

Nouns

  • coincidence that
  • coincidence of

Adverbs

Phrases

  • by coincidence
  • by pure coincidence
  • as if by coincidence
  • what a coincidence
  • it is no coincidence
  • nothing happens by coincidence
  • more than a coincidence

Prepositions

Etymology

LatinFrenchEnglish

Coincidence comes from the Medieval Latin 'coincidentia', meaning 'a falling together'. The prefix 'co-' means 'together', and 'incidere' means 'to fall upon or happen'. The word entered English through French 'coïncidence' in the early 1600s, originally referring to things occurring at the same moment. By the 1700s, it had developed the additional sense of two things matching or agreeing — the 'correspondence' meaning found in formal writing today.