accidental

US /ˌæk.səˈden.t̬əl/
UK /ˌæk.səˈden.t̬əl/
"accidental" picture
1.

accidentel, fortuit

happening by chance or unexpectedly

:
Their meeting was purely accidental.
Leur rencontre était purement accidentelle.
He made an accidental discovery.
Il a fait une découverte accidentelle.
1.

accidentel

a musical note that is not part of the key signature but is introduced by a sharp, flat, or natural sign

:
The composer used an accidental to temporarily alter the pitch of the note.
Le compositeur a utilisé un accidentel pour modifier temporairement la hauteur de la note.
You need to play that F sharp, it's an accidental.
Tu dois jouer ce Fa dièse, c'est un accidentel.