accidental

1 of 2

adjective

ac·​ci·​den·​tal ˌak-sə-ˈden-tᵊl 

1

a

: occurring unexpectedly or by chance

an accidental discovery

Their meeting was purely accidental.

b

: happening without intent or through carelessness and often with unfortunate results

The death was ruled accidental.

2

: arising from extrinsic causes : incidental, nonessential

3

of a bird : appearing outside its normal geographic range, migration route, or season

accidentalness

ˌak-sə-ˈden-tᵊl-nəs 

noun

accidental

2 of 2

noun

1

: a nonessential property

2

a

music : a note foreign to a key indicated by a signature

b

: a prefixed sign indicating an accidental

3

: a bird found outside its normal geographic range, migration route, or season : vagrant

Frequently Asked Questions

What is the difference between accidental and incidental?

Accidental describes what was not planned or intended. It means "happening by accident" or "happening as an accident," as in "an accidental discovery" and "an accidental injury." Incidental typically means "happening as a minor part or result of something else," as in "a chapter that is incidental to the novel's plot." For more information read the full article.

Do you say 'on accident' or 'by accident'?

While both "by accident" and "on accident" are used, "by accident" is far more common.

What does 'accident waiting to happen' mean?

The phrase "an accident waiting to happen" refers to a person or thing that is dangerous or unsafe. For example, a very clumsy person and a rickety ladder might both be referred to as "an accident waiting to happen."

Synonyms of accidental

Adjective

• chance
• inadvertent
• unexpected
• unintentional
• incidental
• casual
• unintended
• unplanned
• fortuitous

Choose the Right Synonym for accidental

accidental, fortuitous, casual, contingent mean not amenable to planning or prediction.

accidental stresses chance.

any resemblance to actual persons is entirely accidental

fortuitous so strongly suggests chance that it often connotes entire absence of cause.

a series of fortuitous events

casual stresses lack of real or apparent premeditation or intent.

a casual encounter with a stranger

contingent suggests possibility of happening but stresses uncertainty and dependence on other future events for existence or occurrence.

the contingent effects of the proposed law

Examples of accidental in a Sentence

Adjective

an accidental discovery of oil

The timing of the announcement was purely accidental.

The death was ruled accidental.

Recent Examples on the Web

Adjective

Unlike conventional industrial robots that rely on rigid structures and external safety barriers, AIR uses a compliant mechanical design intended to reduce the risk of injury during accidental contact. — Jijo Malayil, Interesting Engineering, 9 Nov. 2026

Many children’s medications also have flavorings to get children to take them, increasing risks of accidental overdose. — Laura Tillman, Hartford Courant, 7 Nov. 2026

The Fulton County medical examiner ruled his death accidental and listed the cause as drowning in the setting of psilocybin use. — Christopher Harris, CBS News, 6 Nov. 2026

The artist Lucien Smith died from an accidental overdose of fentanyl and oxycodone, stated the New York City medical examiner’s office. — Devorah Lauter, ARTnews.com, 6 Nov. 2026

Word History

Etymology

Adjective

Middle English, borrowed from Anglo-French accidentel, borrowed from Late Latin accidentālis, from Latin accident-, accidens accident + -ālis -al entry 1

Noun

Middle English, borrowed from Medieval Latin accidentālis, noun derivative of Late Latin accidentālis accidental entry 1

First Known Use

Adjective

14th century, in the meaning defined at sense 2

Noun

14th century, in the meaning defined at sense 1

Rhymes for accidental

• compartmental
• continental
• detrimental
• elemental
• fundamental
• governmental
• incidental
• incremental
• instrumental
• interdental
• monumental
• nonjudgmental

Kids Definition

accidental

1 of 2 adjective

ac·​ci·​den·​tal ˌak-sə-ˈdent-ᵊl 

1

: happening unexpectedly or by chance

an accidental discovery of oil

2

: not happening or done on purpose

an accidental fall

accidentally

-ˈdent-lē 

-ˈdent-ᵊl-ē

adverb

accidental

2 of 2 noun

: a musical note whose pitch is changed (as by a sharp or a flat) from the pitch shown in the key signature