incidentally

incidentally — adverb

1. Said before a remark that is connected to the main topic but is less important —

1.adverbB2
Definition

Said before a remark that is connected to the main topic but is less important — used to add a related thought, ask a related question, or return to an earlier point in a conversation.

Example

Eli and I are going to a concert. Incidentally, do you know if parking is free nearby?

discourse marker introducing a question on a related topic

Sales are up this quarter. Incidentally, I heard the marketing team is getting a bonus.

sentence-initial position linking to a related piece of news

Synonyms
  • by the way

    more informal and conversational; preferred in everyday speech

  • as an aside

    slightly more formal; often used in writing or prepared remarks

  • speaking of which

    used when the new remark is directly triggered by the previous topic

Grammar Patterns

Incidentally, + [question]

Incidentally, + [statement]

Usage Note

Typically placed at the start of a sentence or clause, followed by a comma. Frequently used in both conversation and informal writing to shift focus briefly without changing the subject entirely. Can also appear parenthetically in the middle of a sentence: 'The answer, incidentally, is yes.'

Common Mistakes

The glass fell on the floor incidentally.
The glass fell on the floor accidentally.
'Incidentally' means 'by the way,' not 'by accident.' Use 'accidentally' for unintended events.

2. Said before giving information that the listener or reader did not know before,

2.adverbC1
Definition

Said before giving information that the listener or reader did not know before, often with the effect of making the new fact appear less significant — as if it were merely a side detail rather than the main point.

Example

Charlotte is an award-winning architect. Incidentally, she also teaches design classes at the local university.

introduces a noteworthy additional fact about a person

The Watanabes' kitchen renovation is nearly done. Incidentally, the plumber said the main pipe needs replacing.

Synonyms
  • as an aside

    very close in meaning; emphasises the offhand nature of the remark

  • parenthetically

    more formal and literary; suggests a deliberate written aside

  • additionally

    more neutral and factual; does not carry the downplaying tone

Grammar Patterns

Incidentally, + [new information / statement]

Usage Note

In this sense the speaker or writer is deliberately presenting the new information as if it were of secondary importance, even when the fact itself is significant. Common in formal reports, emails, and presentations where the speaker wants to add a key piece of information without seeming to interrupt the main argument.

Common Mistakes

He forgot his keys incidentally.
Incidentally, he forgot his keys.
When used as a discourse marker, 'incidentally' sounds more natural at the start of the clause rather than attached at the end.

Word family

Synonym discussion

Sense: adverb/1

All three alternatives serve to introduce a remark that departs from the main topic, but they differ in tone and triggering context. 'By the way' is the most informal and natural in casual conversation; it signals a genuine digression without any pretence of structure. 'As an aside' is slightly more formal — it acknowledges the digression explicitly and is common in meetings, lectures, or prepared remarks. 'Speaking of which' is the most tightly connected: it requires that the new remark be directly triggered by something just mentioned, so it cannot introduce a completely fresh topic. 'Incidentally' sits between these in formality — it is at home in both spoken and written English and can introduce anything from a quick question ('Incidentally, where are the keys?') to an important but deliberately understated fact ('Incidentally, the deadline is next Tuesday').

by the way ↗as an asidespeaking of which

Common collocations

Phrases

  • Incidentally, + question
  • Incidentally, + statement
  • …, incidentally, … (parenthetical)

Etymology

LatinFrenchEnglish

Formed in English by adding the suffix '-ly' to 'incidental', which comes from 'incident' + '-al'. 'Incident' traces back through French to Latin 'incidere' — a combination of 'in-' (upon, into) and 'cadere' (to fall). The original Latin meaning was 'to fall upon' or 'to happen'. The modern discourse-marker use — introducing an aside or a side remark — developed in the 17th century, shifting the focus from 'something that happens by chance' to 'something mentioned by the way'.