English Reference

Word

incidentally

Phoneticsin·ci·den·tal·ly, stress on the third syllable

US/ˌɪnsɪˈdɛntəɫi/

UK/ˌɪnsɪdˈɛntəli/

Sentence adverb

Definitions

01by the way

B2 · Upper Intermediate

adv. you use this when you want to add a quick piece of information that is not the main topic.

adv. used as a sentence connector to introduce a remark that is not directly related to the main subject of discussion.

“We had a great time at the party — incidentally, did you see what Sarah was wearing?”

“The report provides a comprehensive overview of the fiscal year; incidentally, it also highlights several areas where the department could reduce waste.”

Usage

Usually placed at the beginning of a sentence or clause to signal a change in topic.

Synonyms

by the wayparenthetically

02by chance

C1 · Advanced Formal

adv. happening as a small part of something else, or by accident.

adv. occurring as a minor consequence or accompaniment to a primary activity or event.

“The two scientists discovered the new chemical incidentally while they were looking for something else.”

“The data was collected incidentally during the primary study, yet it proved to be the most significant finding of the entire research project.”

Usage

Often follows the verb it modifies.

Real-World Examples

“She keeps, incidentally, the Tony she won for playing Jocasta in Oedipus on a shelf by the computer, “next to its friend, Larry Olivier” – an Olivier awarded for the same role.”
The Guardian 24 Sept 2026

Etymology

From incidental + -ly.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

ADVERB

incidentally(B2)

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944EikenEikenTest in Practical English ProficiencyThe English proficiency test from the Eiken Foundation of Japan, widely taken by Japanese students. Grades run from 5 to 1, with Pre-1 and Pre-2 between them.Pre-1
Frequency
Frequent
Level
B2 · Upper Intermediate
Updated

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English Reference