Meaning of ACCIDENTAL in English

ACCIDENTAL

adj. & n.

adj. 1 happening by chance, unintentionally, or unexpectedly. 2 not essential to a conception; subsidiary.

n. 1 Mus. a sign indicating a momentary departure from the key signature by raising or lowering a note. 2 something not essential to a conception. accidentally adv.

[ ME f. LL accidentalis (as ACCIDENT) ]

Concise Oxford English dictionary.      Краткий оксфордский словарь английского языка.