What does "singing" mean?

Singing: from Sing, v. Singing bird. (Zoöl.) (a) Popularly, any bird that sings; a song bird. (b) Specifically, any one of the Oscines. -- Singing book, a book containing music for singing; a book of tunes. -- Singing falcon or hawk. (Zoöl.) See Chanting falcon, under Chanting. -- Singing fish (Zoöl.), a California toadfish (Porichthys porosissimus). -- Singing flame (Acoustics), a flame, as of hydrogen or coal gas, burning within a tube and so adjusted as to set the air within the tube in vibration, causing sound. The apparatus is called also chemical harmonicon. -- Singing master, a man who teaches vocal music. -- Singing school, a school in which persons are instructed in singing.