topic

topic — noun

1. an idea, event, or area of knowledge that people choose to talk or write about —

1.nounA2
Definition

an idea, event, or area of knowledge that people choose to talk or write about — for instance, health in a doctor's meeting, or dinosaurs in a history lesson.

Example

Amihan chose climate change as the topic for his class presentation.

choose [something] as the topic — verb + topic pattern

The main topic of today's staff meeting is the new safety rules.

main topic of [event] — common collocation

Common collocations
  • hot topic
  • topic of conversation
  • topic of discussion
  • bring up a topic
  • cover a topic
  • switch topics
  • discuss a topic
  • broaden the topic
Synonyms
  • subject

    more general than 'topic'; can refer to a whole field of study

  • theme

    suggests a recurring or unifying idea, especially in literature or art

  • issue

    a topic that people disagree about or that has practical importance

  • matter

    a formal or impersonal topic, often in business or official contexts

Grammar Patterns

topic of [subject]

topic for [purpose]

choose/pick a topic

Usage Note

Topic is narrower and more specific than 'subject.' You can talk about the 'subject' of a book generally, but its 'topics' are the individual ideas covered within it.

Common Mistakes

I need to find a topic to write my essay about.
I need to find a topic for my essay.
'topic for' is more natural when stating the purpose of the writing.

2. directly connected to the idea or subject that people are currently discussing o

2.nounB1
Definition

directly connected to the idea or subject that people are currently discussing or studying — used primarily in the phrase 'on topic'.

Example

Please keep your questions on topic during the twenty-minute Q&A session.

keep + on topic — fixed phrasal structure

Every paragraph in your essay should stay on topic and support your main argument.

stay on topic — common verb + phrase

Common collocations
  • keep on topic
  • stay on topic
  • remain on topic
  • perfectly on topic
Synonyms
  • relevant

    the more general term; available in any register

  • pertinent

    more formal than 'on topic'; suggests strong logical relevance

Antonyms

Grammar Patterns

on topic (after verbs: keep, stay, remain)

on-topic (hyphenated before a noun)

Usage Note

Nearly always appears in the fixed phrase 'on topic' after a linking verb (be, stay, keep, remain). When placed before a noun, use a hyphen: 'an on-topic remark.'

Common Mistakes

Your question is very on-topic.
Your question is very on topic.
After a verb, do not use a hyphen. The hyphen is only needed when the phrase comes before a noun: 'an on-topic question.'

3. not connected to the idea or subject that people are currently discussing or stu

3.nounB1
Definition

not connected to the idea or subject that people are currently discussing or studying — used primarily in the phrase 'off topic'.

Example

His question about the cafeteria menu was completely off topic in the physics lesson.

completely off topic — intensifier + phrase

The teacher asked the students to stop sharing off-topic stories during group work.

off-topic as hyphenated adjective before a noun

Common collocations
  • completely off topic
  • go off topic
  • stray off topic
  • way off topic
Synonyms
  • irrelevant

    the more general and formal term; can describe any lack of connection

  • unrelated

    suggests two things simply lack a connection, not necessarily that one distracts from the other

Antonyms

Grammar Patterns

off topic (after verbs: go, be)

off-topic (hyphenated before a noun)

Usage Note

Appears mainly in the fixed phrase 'off topic' after a linking verb. Before a noun, hyphenate: 'an off-topic comment.' The verb 'go off topic' is common in classroom and meeting settings to describe when a discussion moves away from the original subject.

Common Mistakes

The student kept going off-topic.
The student kept going off topic.
In the verb phrase 'go off topic', no hyphen is needed because the phrase follows a verb.
Idioms

off topic

idiom

Not related to the main subject being discussed.

Maya's question about the budget was completely off topic.

Why did you bring up a movie that is off topic?

on topic

idiom

Related to the main subject being discussed.

Diego's presentation stayed on topic throughout the meeting.

Please keep your comments on topic during the debate.

Word family

  • topical
    adjectiveB2
  • topically
    adverbC1
  • topicality
    nounC1

Synonym discussion

Sense: noun/1

'Subject' is the broadest of these words — it can refer to an entire field of study ('the subject of chemistry') or a general area of interest. 'Topic' is narrower: it points to a specific idea within a larger subject. The 'subject' of a meeting might be 'school safety,' while one 'topic' discussed is 'new emergency drills.' 'Theme' suggests a unifying or recurring idea, especially in creative works — 'love' is a theme in many novels, not just a topic. 'Issue' implies disagreement or practical stakes ('the issue of rising rents'), making it heavier than 'topic.' 'Matter' is formal and impersonal, common in business contexts ('the matter of budget cuts'). In everyday conversation, use 'topic' for what you're talking about right now, and 'subject' for broader areas of knowledge or interest.

subject ↗theme ↗issue ↗matter ↗

Common collocations

Nouns

Adverbs

  • directly (on topic)
  • completely (off topic)
  • totally (off topic)
  • perfectly (on topic)
  • broadly (on a topic)

Phrases

  • topic of conversation
  • range of topics
  • bring up a topic
  • switch topics
  • stay on topic
  • go off topic

Prepositions

  • on (topic)
  • off (topic)
  • about (a topic)
  • for (a topic)
  • of (a topic)

Etymology

GreekLatinFrenchEnglish

'Topic' comes from the Greek word 'topos,' meaning 'place' or 'commonplace.' In ancient Greece, 'topoi' (plural) were standard arguments or themes that speakers would keep in mind — like a mental 'place' to find ideas. The word passed into Latin as 'topica' (the art of finding arguments), then into French as 'topique,' and finally into English in the 1400s, where it came to mean a subject for discussion.