bebung

from The Century Dictionary.

• noun A certain pulsation or trembling effect given to a sustained note, in either vocal or instrumental music, for the sake of expression.
• noun Specifically— An effect produced upon the obsolete clavichord by balancing the finger on the key so as slightly to rub the tangent against the string and thus prolong the tone with a gentle pulsation.
• noun An effect, common in violin-playing, produced by rocking the finger of the left hand in stopping a string so as to produce a slight waver or tremolo in the pitch.
• noun An effect in singing produced by a slight unsteadiness in the breath so as to cause a waver both in pitch and in resonance. See tremolo and vibrato.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Music) A tremolo effect, such as that produced on the piano by vibratory repetition of a note with sustained use of the pedal.