1. (

• accidental

) a musical notation that makes a note sharp or flat or natural although that is not part of the key signature ;

1. (

• accidental ,
• inadvertent

) happening by chance or unexpectedly or unintentionally; "with an inadvertent gesture she swept the vase off the table"; "accidental poisoning"; "an accidental shooting" ;

2. (

• incidental ,
• nonessential ,
• accidental

) not of prime or central importance; "nonessential to the integral meanings of poetry"- Pubs.MLA; "the character's motives remain accidental to the plot" ;