What is the meaning of Ding-dong?

Closely fought.

One of several sounds that might be made by a bell.

A woman's breast.

A penis.

A fight, an argument; a set-to.

An idiot.

An attachment to a clock by which the quarter hours are struck upon bells of different tones.

To ring with two tones, like a bell swinging back and forth.

a sound made by a bell

Source: wiktionary.org