A surname.

A surname from German of English-speakers. / (music) Johann Sebastian Bach, a German organist and composer.

A surname from Vietnamese.

(of a gun, cannon, Bunsen burner, etc.) To fire in the opposite direction, for example due to an obstruction in the barrel.

(firefighting) Alternative spelling of back fire

(figuratively) A situation where the use of many different languages is a source of confusion.

(idiomatic) Without somebody's knowledge; secretly.

A pale blue color.

Of a pale blue color.

(music) A sequence of four notes (B flat, A, C, B natural), included in a piece of music as a homage to Johann Sebastian Bach.