Definition of "Ballast" :

noun: any heavy material used to stabilize a ship or airship

noun: an electrical device for starting and regulating fluorescent and discharge lamps

noun: a resistor inserted into a circuit to compensate for changes (as those arising from temperature fluctuations)

noun: an attribute that tends to give stability in character and morals; something that steadies the mind or feelings

noun: coarse gravel laid to form a bed for streets and railroads

verb: make steady with a ballast